Assessment of Electromagnetic Field Impacts)

Cross London Rail Links Limited

Crossrail Assessment of Atmospheric Emissions & Air Quality Impacts (Assessment of Electromagnetic Field Impacts)

Volume IV of IV

Crossrail Reference: 1E0320-G0E00-00004

February 2005

Mott MacDonald Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV

Crossrail Assessment of Atmospheric Emissions & Air Quality Impacts (Assessment of Electromagnetic Field Impacts)

1E0320-G0E00-00004

This document has been prepared for the titled project or named part thereof and should not be relied upon or used for any other project without an independent check being carried out as to its suitability and prior written authority of Mott MacDonald being obtained. Mott MacDonald accepts no responsibility or liability for the consequences of this document being used for a purpose other than the purposes for which it was commissioned. Any person using or relying on the document for such other purpose agrees, and will by such use or reliance be taken to confirm his agreement to indemnify Mott MacDonald for all loss or damage resulting therefrom. Mott MacDonald accepts no responsibility or liability for this document to any party other than the person by whom it was commissioned.

To the extent that the report commissioned is to be based on information supplied by other parties, Mott MacDonald accepts no liability for any loss or damage suffered by the client, whether contractual or tortious, stemming from any conclusions based on data supplied by parties other than Mott MacDonald and used by Mott MacDonald in preparing this report.

Cross London Rail Links Limited 1, Butler Place LONDON, SW1H 0PT

Tel: 020 7941 7600 Fax: 020 7941 7703 www.crossrail.co.uk

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List of Contents

Volume I – Technical Report, Emissions and Air Quality Assessment

Volume II – Drawings and Figures

Volume III – Data and Assumptions

Volume IV – Technical Report, Electromagnetic Field Assessment

Sections and Appendices

1 Introduction 1 1.1 Overview 1 1.1.1 Introduction to Crossrail 1 1.1.2 Route Overview 2 1.2 Reporting Structure 3

2 Scope and Methodology 5 2.1 Scoping 5 2.1.1 Potential Impacts 5 (i) Construction Phase 5 (ii) Operational Phase 5 2.1.2 Definition of Scope 5 (i) Spatial Scope 5 Surface Railways West 6 Tunnelled Railways Central 6 Surface Railways East 6 (ii) Technical Scope 7 (iii) Temporal Scope 7 2.1.3 Inventory of Receptors 7 2.2 Establishment of a Baseline 7 2.3 Prediction of Impacts 8 2.4 Evaluation of Impacts 8 (i) Guidelines 8 (ii) Impact of Harmonic Currents 10 (iii) Interference with Electronic Equipment. 11 (iv) Significance 11

3 Western Route Section 13 3.1 Methodology Used to Evaluate EMF Impacts Western Route 13

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3.2 Typical Cross Section of Great Western Main Line 14 3.3 Overhead Traction Power Supplies (25 kV AC) 16 3.4 Findings from the Typical Section Of GWML 17 3.5 Modelling of GWML by Selected Sections 18 3.5.1 Paddington Station to Old Oak Common Depot (Route Windows C2 to W3) 18 3.5.2 Ealing Broadway Station to West Ealing Station (Route Window W5 – W6) 19 3.5.3 Hayes & Harlington Station to Stockley Flyover (Route Window W10 – W11) 19 3.5.4 Stockley Flyover to West Drayton Station (Route Window W11 – W13) 21 3.5.5 Iver Station to Langley Station (Route Window W14 – W16) 23 3.5.6 Langley Station to Slough Station (Route Window W16 – W18) 23 3.5.7 Slough Station to Burnham Station (Route Window W18 – W21) 25 3.5.8 Burnham Station to Taplow Station (Route Window W21 – W23) 26 3.5.9 Taplow to Maidenhead (Route Window W23 – W25) 28 3.6 Summary of EMF Impacts along GWML Paddington to Maidenhead 28 3.6.1 Protection of Public Health 28 3.6.2 Protection of Occupational Health 29 3.6.3 Interference with Electronic Equipment 29 3.6.4 Summary 29 3.7 Buildings Where Magnetic Field Strengths Exceed Interference Levels 30

4 Central Route Section 33 4.1 Extent of Study 33 4.2 Methodology 33 4.2.1 Load Currents 34 4.2.2 Earth Currents 35 4.3 Magnetic Fields at Susceptible Properties 35 4.4 Susceptible Properties – Maximum Fields with 5% Earth Current 36 4.5 Susceptible Properties – Maximum Fields with 10% Earth Current 36

5 Eastern Route Section 39 5.1 Extent of Study 39 5.2 Crossrail Service on Existing 25 kV AC Electrified Railway 39 5.3 Crossrail Service on Existing 750 V DC Electrified Railway 39 5.4 New Alignments Necessitated by Crossrail Works 39 (i) Pudding Mill Lane 39 (ii) Gidea Park Sidings 39 (iii) Shenfield Station and Sidings 40 (iv) Custom House 40 (v) Romford Depot 40 (vi) Custom House to Abbey Wood 40

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5.5 Prediction of Impacts 40 5.6 Methodology 40 5.7 Crossrail Central & Eastern Power Supplies (25 kV AC) 43 5.8 Window C13 – Pudding Mill Lane 44 5.8.1 Choice of Section 44 5.8.2 Pudding Mill Lane – Results 46 5.9 Window NE11 – Gidea Park Sidings 46 5.9.1 Choice of Section (1) 46 5.9.2 Gidea Park Sidings (Section 1) – Results. 47 5.9.3 Choice of Section (2) 48 5.9.4 Gidea Park Sidings (Section 2) – Results. 49 5.10 Window NE17 – Shenfield Station 50 5.10.1 Choice of Section 50 5.10.2 Shenfield Sidings – Results. 51 5.11 Window SE2 – Custom House 52 5.11.1 Choice of Section (1) 52 5.11.2 Custom House (Section 1) – Results. 54 5.11.3 Choice of Section (2) 55 5.11.4 Custom House (Section 2) – Results. 57 5.12 Window NE9 – Romford Depot 58 5.12.1 Sections for Modelling 58 5.12.2 Section 1 – Turn-off from GEML tracks. 58 (i) Choice of Section 1 58 (ii) Romford Depot – Section 1 Results 59 5.12.3 Section 2 – West of Jutsums Lane Bridge. 60 (i) Choice of Section 2 60 (ii) Romford Depot – Section 2 Results 61 5.12.4 Section 3 – Closest approach to Housing on Depot Approaches 62 (i) Choice of Section 3 62 (ii) Romford Depot – Section 3 Results 63 5.12.5 Section 4 – Stabling Sidings and Oldchurch Hospital 64 (i) Choice of Section 4 64 (ii) Romford Depot – Section 4 Results 65 5.13 Window SE2 – SE8 Custom House to Abbey Wood 66 5.13.1 Window SE2-SE8 – Surface Railway 67 5.13.2 Window SE2-SE8 – Connaught and Thames Tunnels 68 5.14 Summary of Findings – Eastern Route Sections 70

6 Summary of Conclusions and Recommendations 73 6.1 Western Route Section 73 6.2 Central Section 73 (i) Susceptible Buildings from the Tunnels Obstruction Study 73 6.3 Eastern Route Section 74

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Tables Table 2-1 Limits for Electric and Magnetic Fields...... 9 Table 2-2 – NRPB/ICNIRP Exposure Guidelines for EMF ...... 9 Table 2-3 Typical Traction Supply Harmonic Content...... 10 Table 2-4 – EMF Limits for Assessment...... 12 Table 3-1 Basic Assumptions made in assessing EMFs...... 14 Table 3-2 EMF on Typical GWML Section ...... 17 Table 3-3 EMF Results : Paddington Station to Old Oak Common Depot...... 18 Table 3-4 EMF Results: Ealing Broadway Station to West Ealing Station ...... 19 Table 3-5 EMF Results : Hayes & Harlington Station to Stockley Flyover ...... 21 Table 3-6 EMF Results: Stockley Flyover to West Drayton Station ...... 22 Table 3-7 EMF Results: Iver Station to Langley Station...... 23 Table 3-8 EMF Results : Langley Station to Slough Station...... 25 Table 3-9 EMF Results : Slough Station to Burnham Station...... 26 Table 3-10 EMF Results : Burnham Station to Taplow Station ...... 27 Table 3-11 EMF Results : Taplow to Maidenhead ...... 28 Table 3-12 Summary of EMF Levels from Typical and Representative Crossrail Track Sections at the Nearest Railway Boundaries...... 30 Table 3-13 – Buildings within 10 m of GWML Electrified Tracks...... 31 Table 4-1 – Central Area Traction Loads ...... 34 Table 4-2 - Fields with 5% Earth Current ...... 36 Table 4-3 - Fields with 10% Earth Current ...... 37 Table 5-1 Basic Assumptions made in assessing EMFs...... 41 Table 5-2 – Pudding Mill Lane EMF Results ...... 46 Table 5-3 – Gidea Park Sidings (Section 1) EMF Results...... 48 Table 5-4 – Gidea Park Sidings (Section 2) EMF Results...... 50 Table 5-5 – Shenfield Sidings – EMF Results...... 52 Table 5-6 – Custom House (Section 1) – EMF Results...... 55 Table 5-7 – Custom House (Section 2) – EMF Results...... 57 Table 5-8 – Romford Depot (Section 1) – EMF Results...... 59 Table 5-9 – Romford Depot (Section 2) – EMF Results...... 61 Table 5-10 – Romford Depot (Section 3) – EMF Results...... 63 Table 5-11 – Romford Depot (Section 4) – EMF Results...... 66 Table 5-12 – Properties in Windows SE2-SE8...... 67 Table 5-13 – EMF Results Windows SE2-SE8 (Surface)...... 68 Table 5-14 – Window SE2-SE8, Vertical Profiles...... 69 Table 5-15 – EMF Results Windows SE2-SE8 (Tunnels) ...... 69 Table 5-16 – Maximum EMFs from Crossrail OLE (Eastern Route Sections)...... 71

Figures Figure 1-1: Overview of Crossrail Route ...... 1 Figure 3-1 – Typical Section of GWML (4-track) after Electrification...... 15 Figure 3-2 – Field Plots for Typical GWML 4-track Section...... 15 Figure 3-3 – Schematic of Power Supplies, West ...... 16 Figure 3-4 –Section Diagram...... 20 Figure 3-5 – Section Diagram...... 22

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Figure 3-6 – Sheet 333, Section Diagram ...... 24 Figure 3-7 – Section Diagram...... 26 Figure 4-1 – Typical Tunnel Section...... 34 Figure 5-1 – Typical Section of Main line Twin-track...... 42 Figure 5-2 – Field Plots for Twin Track 25kV Electrified Railway...... 43 Figure 5-3 – Schematic of Power Supplies, Central and East OLE ...... 44 Figure 5-4 – Pudding Mill Lane - Map ...... 45 Figure 5-5 – Pudding Mill Lane – Plan ...... 45 Figure 5-6 – Gidea Park Sidings Map (Section 1)...... 47 Figure 5-7 - Gidea Park Sidings – Plan, Section 1...... 47 Figure 5-8 – Gidea Park Sidings Map (Section 2)...... 49 Figure 5-9 - Gidea Park Sidings – Plan, Section 2...... 49 Figure 5-10 – Shenfield Sidings Map ...... 51 Figure 5-11 – Shenfield Sidings – Plan ...... 51 Figure 5-12 – Custom House Map (Section 1)...... 53 Figure 5-13 – Custom House – Plan, Section 1 ...... 54 Figure 5-14 – Custom House Map (Section 2)...... 56 Figure 5-15 – Custom House – Plan, Section 2 ...... 56 Figure 5-16 – Romford Depot Map (Section 1) ...... 58 Figure 5-17 – Romford Depot – Plan of Section 1...... 59 Figure 5-18 – Romford Depot Map (Section 2) ...... 60 Figure 5-19 – Romford Depot – Plan of Section 2...... 61 Figure 5-20 – Romford Depot Map (Section 3) ...... 62 Figure 5-21 – Romford Depot – Plan of Section 3...... 63 Figure 5-22 – Romford Depot Map (Section 4) ...... 65 Figure 5-23 – Romford Depot – Plan of Section 4...... 65

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Glossary

Abbrev. Definition °C Degrees centigrade. A Ampere. AC Alternating current. Bulk Supply Typically, in England and Wales, a substation at which NGC supply power to the Point DNO networks (at 132 kV or below). In Scotland and N. Ireland, a substation which essentially serves the same role. Bus, busbar A conductor (which may literally be a group of copper bars) used to connect a number of switches or circuit breakers together. Cable Unless otherwise qualified, an electrical circuit installed underground with insulated conductors surrounded by a sheath and/or armour for protection. Capacity Unless otherwise qualified, the maximum continuous output (MW or MVA) which a circuit, transformer, generator is capable of. Catenary Generic term covering the contact and support wire(s) suspended over railway tracks for power collection by locomotives or EMUs. Unless otherwise qualified, deemed to be permanently energised at 25 kV AC rms (relative to rails/earth). CB Circuit breaker. CRE Conductor Rail Equipment. Generic term for all 750 V DC traction power supplies. DC Direct current. DLR Docklands Light Rail. (A tramway system serving the Docklands area of London, using a 750 V DC third rail power supply). DNO Distribution Network Operator. The organisation responsible for the physical assets (the "wires") employed in power distribution. E.R. G5/4 See "G5/4". E.R. P2/5 See "P2/5". E.R. P24 See “P24”. E.R. P28 See "P28". EA Electricity Association. Body responsible for maintaining certain standards,previously under the control of the Electricity Supply Industry organisations. EMC Electromagnetic Compatibility. Apparatus or applications can be certified as being immune to external fields over a range of frequencies up to agreed limits. Likewise, the interference generated by apparatus or applications is limited over a range of frequencies. EMF Electric and Magnetic Field(s). EMU Electric Multiple Unit. A number of railway coaches permanently coupled, with one (or more) motor coaches, driving positions each end and means to take power from an external power sources via overhead wires or electrified rails. Firm capacity Firm capacity is usually applied to substations or feeders where two or more circuits are installed, and is the remaining capacity with one circuit out of service. See “N—1”. G (prefix) Giga- (1e9). G5/4 Planning limits for harmonic voltage distortion and the connection of non-linear equipment to transmission and distribution networks in the UK. GEML Great Eastern Main Line.

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Abbrev. Definition Grid A generic term referencing the interconnected power transmission system to which load and generation are connected, including the 400 kV and 275 kV networks, and parts of the 132 kV network. Grid Substation Typically, a 132/33 kV substation. In England and Wales, a substation owned by the DNO, serving a number of Primary Substations. In Scotland and N. Ireland, a substation which essentially serves the same role. GWML Great Western Main Line. HV (as a noun) High Voltage (>36 kV). HV (as an Higher voltage (e.g. the HV winding of a transformer). adjective) Hz Herz (cycles/s). ICNIRP International Commission on Non-Ionising Radiation Protection. J Joule, unit of energy =Ws, the product of watts and seconds. K Kelvin, temperature rise or fall, expressed as the difference between two temperatures measured in °C. (Not to be confused with the special case where one of the reference temperatures is Absolute Zero). k (prefix) Kilo- (1e3). kg Kilogram, unit of mass. kVA Apparent power, kilovolt-amperes (VA*1e3). kvar Reactive power (var*1e3). kW Real power, kilowatt (watts*1e3). kWh Kilowatt-hour, unit of energy = 3.6 MJ. lagging Electrical current lags the voltage, as when supplying an inductive reactor load. LE See "London Electricity". leading Electrical current leads the voltage, as when supplying a capacitive load. Line Unless otherwise qualified, an electrical circuit constructed above ground with conductors supported on insulators mounted on poles, towers or similar structures. Line voltage Voltage between any two lines of a three-phase supply (e.g. 400 V) In power networks this is the usual default if the voltage value is not designated specifically. Load Unless otherwise qualified, the three-phase load (MW) taken by a group of consumers at the time of highest demand (usually during a winter cold snap). Load factor The factor relating capacity to energy generated or used over a period (usually one year unless otherwise defined). Recorded energy in kWh or multiples thereof is divided by the number of hours in the period in order to obtain a mean power output, which is then divided by maximum capacity to give load factor. London The organisation (currently EDF Energy, LPN or London Power Networks, was Electricity "24/7", "LEB" etc.) responsible for the construction and operation of the power transmission networks in London at 132 kV and below. Note at the fringes of the proposed Crossrail routes, other electricity operators ("Distribution Network Operators") may be responsible for local power networks. LV (as a noun) Low Voltage (<=1000 V). LV (as an Lower voltage (e.g. the LV winding of a transformer). adjective) m Metre. M (prefix) Mega- (1e6). m (prefix) Milli- (1e-3). main or mains A term usually applied to the network of LV cables or OHL run down streets or public thoroughfares in order to supply adjacent properties.

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Abbrev. Definition MV Medium Voltage (>1-36 kV). MVA Apparent power, megavolt-amperes (VA*1e6). Mvar Reactive power, megavar (var*1e6). MW Real power, megawatt (watts*1e6). N Newton (unit of force). n (prefix) Nano- (1e-9). N—1 Shorthand means of defining a level of security, whereby any system can deliver its design loads or capacity with one (the largest) component out of service for any reason. Neutral Section Insulated section of catenary located between two sources of traction power. NGC National Grid Company or successors. Responsible for operating the 400 kV and 275 kV networks in England and Wales. NRPB National Radiological Protection Board. Off-circuit A device, typically a facility to change transformer taps, which is only permitted to be used with the circuit off load and de-energised. OHL, Overhead Unless otherwise qualified, an electrical circuit constructed above ground with line conductors supported on insulators mounted on poles, towers or similar structures. Ohm (Ω) Ohm (unit of electrical resistance). OLE Overhead Line Equipment. Generic term for all 25 kV AC traction power supplies. OLTC On-load tap changer (for changing the turns ratio, hence the output voltage, on a transformer). p.f. Power factor, the ratio W/VA. P2/5 Engineering Recommendation P2/5 is the security standard applicable to most distribution circuits, and requires a capability to support load in the event of outages of any description for loads above 1 MW. More stringent requirements are imposed for larger levels of load. P24 Engineering Recommendation, AC Traction Supplies to British Rail. P28 Planning limits for voltage fluctuations in the UK for 132kV and below. Phase voltage Voltage between any line and neutral of a three-phase supply (e.g. 230 V). Protection Unless the context indicates otherwise, the devices provided to detect and isolate a faulty electrical circuit, usually associated with one or more circuit breakers. Rating Unless qualified, the maximum continuous current which can be carried by an item of electrical apparatus without its internal temperatures exceeding prescribed limits with maximum design ambient temperatures. Rms Root mean square. The value of an AC quantity (current, voltage etc.) by which it is designated, which is equivalent in terms of power and energy to a DC current and voltage of the same magnitude. Rmu or r.m.u. Ring-main unit. A switching device for use at MV, typically comprising two load switches and a fused or circuit-breaker tee-off. s Second. S Siemen (1/ohm). S/S Substation. security In general, the provision of redundant circuits or components in order to enable supplies to be maintained in the event of a planned or forced outage. See "P2/5". Substations An installation where electrical power at a higher voltage is transformed to a lower voltage and connected to a number of outgoing circuits by switchgear. Summer Rating Equipment ratings (q.v.) with ambient temperatures at maximum summer values.

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Abbrev. Definition Switchgear An assembly of devices, usually but not necessarily circuit-breakers, provide to connect and disconnect electrical circuits from a source of supply. symmetrical When applied to an alternating-current quantity, that component of the waveform which is symmetrically displaced above and below zero. t Tonne, unit of mass = 1000 kg. T or tesla A unit of magnetic flux density, related (in free space) to field strength by the -7 -4 relationship that 1 A/m=4. .10 .T (T=tesla). 1 tesla = gauss * 10 . Traction Current Maximum current flowing in the catenary supplying one or more trains. V Volt. VA Volt-amperes (the product of volts and amps). var Volt-amperes reactive (The var is an SI unit (ISO 1000) which supersedes the archaic form of “VAr”). W Watts, unit of power. µ (prefix) Micro- (1e-6). µT Micro-tesla. See “T or tesla”. In free space, approximately, 1 A/m=1.25 µT. θ (as in cos θ) Angle between current and voltage, cos θ = power factor.

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1 Introduction

1.1 Overview

1.1.1 Introduction to Crossrail

Crossrail is a major new cross-London rail link project that has been developed to serve London and the southeast of England. Crossrail will support and maintain the status of London as a world city by providing a world class transport system. The project includes the construction of a twin-bore tunnel on an east-west alignment under central London and the upgrading of existing National Rail lines to the east and west of central London. The Crossrail route is shown in Figure 1.1.

Figure 1-1: Overview of Crossrail Route

The project will enable the introduction of a range of new and improved rail journeys into and through London. It includes the construction of seven central area stations, providing interchange with London Underground, National Rail and London bus services, and the upgrading or renewal of existing stations outside central London. Crossrail will provide fast, efficient and convenient rail access to the West End and the City by linking existing routes from Shenfield and Abbey Wood in the east with Maidenhead and Heathrow in the west.

Crossrail will be a significant addition to the transport infrastructure of London and the southeast of England. It will deliver improved services for rail users through the relief of crowding, faster journeys and the provision of a range of new direct journey opportunities.

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The project will also have wider social and economic benefits for London and the southeast of England.

1.1.2 Route Overview

Crossrail’s route has four distinct sections: a central section within central London and, outside central London, western, northeastern and southeastern sections. The boundaries of these route sections are shown in the schematic maps in Volume I (see below).

In the west, Crossrail will use the Great Western Main Line between Maidenhead and Westbourne Park. The existing 25 kV overhead electrification between Paddington and Airport Junction will be extended to Maidenhead and bridge alterations will be undertaken as necessary. The main infrastructure changes are the construction of a flyover structure (the Stockley flyover) to allow Crossrail trains to access the existing tunnelled spur to Heathrow and the provision of a rail underpass (a dive-under) west of Acton Yard. A new line, within the existing railway corridor, will be provided between Langley and West Drayton. Enhancements will also be made to stations, with the most significant works being at Ealing Broadway, Southall, Hayes and Harlington, West Drayton, Slough and Maidenhead. New stabling sidings are also proposed at Old Oak Common, West Drayton and west of Maidenhead station.

The central route section will consist largely of a twin-bore tunnel beneath central London with portals at Royal Oak in the west, Pudding Mill Lane in the northeast and Victoria Dock Road in the southeast. The central route section extends from a point around 200m west of the A40 Westway to a point around 500m to the east of the portal at Pudding Mill Lane in the northeast and a point just to the east of Poplar Dock and the A1206 Prestons Road in the Isle of Dogs in the southeast. New stations and associated structures, such as ventilation shafts, will be provided along this part of the route.

On the northeast route section, Crossrail will use the existing Great Eastern Main Line between Pudding Mill Lane and Shenfield. The main infrastructure changes are a new train maintenance depot west of Romford station and the reinstatement of a track between Goodmayes and Chadwell Heath. Enhancements will also be made to stations, with the most significant works being proposed at Ilford and Romford. This route has existing 25kV overhead electrification. New stabling facilities will be provided at Gidea Park.

The southeast route section runs between a point to the east of the Isle of Dogs station and the eastern terminus at Abbey Wood, where Crossrail will serve a reconstructed station. Crossrail will operate in a twin-bore tunnel to Victoria Dock portal where it will serve a reconstructed station at Custom House. The route will then follow the existing alignment currently used by the North London Line through the Connaught Tunnel to Silvertown. At North Woolwich, a new twin-bore tunnel to Plumstead, referred to as the Thames Tunnel, will pass beneath the River Thames. Two new tracks will be provided between Plumstead and a point east of Abbey Wood station to accommodate Crossrail services on the North Kent Line corridor. This route will be provided with 25kV overhead electrification on the Crossrail lines.

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1.2 Reporting Structure

Air quality and emissions reporting consists of four volumes: • Volume I – Technical Report on the assessment of emissions and air quality. • Volume II – Drawings. • Volume III – Data and Assumptions. • Volume IV – Technical Report (Assessment of Electromagnetic Field Impacts).

This report, Volume IV, is structured as follows: • Section 2 – outlines the methodology, scope and evaluation criteria applied during the assessment. • Sections 3, 4 and 5 present the results of the assessment of electromagnetic fields in terms of environmental and occupational health, and potential interference with electronic equipment. • Section 6 includes a number of conclusions and recommendations for mitigation.

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2 Scope and Methodology

2.1 Scoping

2.1.1 Potential Impacts

Large scale electrified rail schemes will generate electromagnetic fields which have the potential to have public and occupational health effects and may also interfere with electronic equipment. These potential effects can be considered in terms of the construction and operational phases.

(i) Construction Phase

The power supply to electrical equipment associated with construction activities phase would not be of sufficient power rating to generate electromagnetic fields of significant strength. The possible exceptions to this are the mains feed to the tunnel boring machines and potential for interference due to tall structures such as tower cranes.

The tunnel boring machines will be connected to the electricity grid via high voltage power cables. No electric fields are generated by the cable and, because it is a balanced supply with negligible stray current, there would be extremely low magnetic fields. Tower cranes will include variable speed drives that may cause some local electrical interference (within tens of metres). This can be controlled appropriately by filters and screening. EMF from these sources is not considered significant and has not been assessed further.

Tower cranes may induce a shadow effect on local reception of radio and television broadcasts. Although cranes can be positioned overnight to minimise this effect, should complaints occur, there is little else that can be achieved and hence, has not been assessed further.

(ii) Operational Phase

The potential for impacts associated with electromagnetic fields during the operational phase are limited to public and occupational health effects of electric and magnetic fields, and the potential interference of magnetic fields with electronic equipment.

2.1.2 Definition of Scope

(i) Spatial Scope

This assessment considers the potential electro-magnetic field impacts of new electrification, new track alignments and new tunnelled sections of the route. A number of aspects are considered, including different safety and interference levels from EMF and the presence of receptors within different magnitudes of EMF.

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For much of the route there are existing electrified sections producing electro-magnetic fields due to current operations. The quantity of the route that is electrified varies depending on the section and thus the scoping of the assessment has been split into three sections: western; central; and eastern. These are as described in Volume I.

Surface Railways West

The principal requirement for investigation of EMF levels is the route of the Great Western Mail line (GWML) from Paddington to Maidenhead, in particular the planned electrification of the route from the Stockley Flyover to Maidenhead.

The existing railway to Heathrow is already electrified at 25 kV overhead, and from Stockley Flyover, runs almost entirely in tunnels. EMF impacts would be insignificant and hence, this section is not included in this assessment.

Note that one of the previously considered options of extending Crossrail beyond Maidenhead to Reading was taken into account when selecting the maximum load currents for the purposes of evaluating magnetic field emissions for this assessment.

Tunnelled Railways Central

This aspect of the assessment considered the interference potential of EMF in tunnels across the central route section considering both the horizontal separations and alignments of the tunnels.

From geological and engineering detail provided by CLRL the range of depths from ground surface to rail level was generally 25 m or greater, with minimum values away from the immediate vicinity of tunnel portals 17–19 m. A typical depth of 12 m was considered close to the tunnel portals

Surface Railways East

All of the eastern section, with the exception of the extension within the southeast section, is on the existing electrified Great Eastern line. The principal impacts, in terms of EMF, are associated with proposed new alignments and increased catenary current loading associated with additional trains. The southeast extension would be over existing tracks but with traction power supply converted from CRE to OLE.

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(ii) Technical Scope

Calculations of electric and magnetic fields have been undertaken to establish that: • The magnitude of electric and magnetic fields is within guidelines issued for the purposes of assessing a possible risk to public health. • Interference with adjacent conductors, which may be coupled to either or both the electric and magnetic fields, is at a sufficiently low level to prevent danger or malfunction.

An electrical conductor that carries voltage relative to another conductor or earth will establish an electric field within the space surrounding the conductor. Similarly, if the conductor is carrying electric current, a magnetic field is established around the conductor.

At low frequencies typical of railway power supplies (162/3 – 60 Hz, and harmonics up to a few kHz) electric and magnetic fields can be modelled, particularly when, as is normally the case, the fields are 2 dimensional, surrounding longitudinal power conductors.

Emissions from power supplies will occur at higher frequencies, up into the radio frequency bands, caused, for example, by arcing from the pantograph and possibly high-speed switching in solid-state control circuitry. The level of such emissions will not present a hazard to health, and if other interference effects exist, such as interference to radio and television broadcasts, these would be the subject of independent investigation by the telecommunications authorities to determine appropriate mitigation measures. Emissions from power supplies have not, therefore, been included within this assessment.

Where Crossrail services run over existing 25 kV AC electrified track, there will be no impact on EMFs, save for an increase or decrease in magnetic fields if the total catenary current changes from present levels. This assessment includes for such circumstances.

(iii) Temporal Scope

The assessment of EMF focuses on the year of operations starting with general comments made regarding potential construction impacts.

2.1.3 Inventory of Receptors

At any point in the route where realignment or electrification of tracks is proposed, the EMF impacts have been assessed at properties alongside the railways, on railway workers and/or on passengers.

2.2 Establishment of a Baseline

No baseline has explicitly been established of the background levels of EMF. This assessment has screened out areas where there are no anticipated changes to electrical and line configuration and therefore EMF. The remaining areas include stretches of track that are not currently electrified, but will be under Crossrail, and lengths of track that require

7 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV realignment. In these areas it is anticipated that the structure of EMFs will change and have therefore been assessed.

2.3 Prediction of Impacts

Mott MacDonald has developed an in-house computer program for calculating and plotting electric and magnetic fields surrounding power lines. The program can handle up to 60 conductors with user freedom to specify the voltage, current and respective phase angles applied to each conductor, including earthed conductors with zero voltage applied.

The program requires sufficient information to define the self and mutual capacitances and inductances of every conductor, also taking the ground plane into account (capacitance only).

In the general case the field magnitude varies in space and time with an alternating current field, and if more than one phase is present, a hypothetical charged particle in the field would describe an elliptical path. The program defines the field magnitude and direction in terms of the major axis of this ellipse. With a single-phase supply, the ellipse degenerates to a straight line.

A tabulation is generated by the program of field magnitudes and directions at user selected intervals along the elevation line previously chosen. Typically this might be a notional head height of 1.8 m.

Note that the illustrations of gantry or mast supports for the catenary are solely symbolic. It is not intended to be fully representative, noting that the choice will be a matter of detail engineering at a later stage. The choice of support has no material effect on the electric or magnetic fields.

2.4 Evaluation of Impacts

(i) Guidelines

The principal authority in the UK for setting guideline levels for the levels of electromagnetic fields is the National Radiological Protection Board (NRPB). Recommended exposure limits have recently been updated (bringing them into line with the latest research and recommendations from other European or international bodies, in particular the International Commission on Non-Ionising Radiation Protection (ICNIRP) and the European Council recommendation made to National governments (1999/519/EC) for harmonising EMF limits.

Within the literature, various distinctions are made between the level of the fields and the degree of exposure. For simplicity, these may be summarised as follows:

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Table 2-1 Limits for Electric and Magnetic Fields

Term Application Basic Level A quantity expressed as a current density in the human body (at lower frequencies) or SAR (specific energy absorption rate) at higher frequencies. Reference Level A quantity provided for practical exposure assessment purposes to determine (NRPB uses the whether the Basic Levels are likely to be exceeded. The units are those of term Investigation external EMFs such as kV/m (electric field) and µT (magnetic flux density). If Level) an EMF exceeds a Reference Level this is not necessarily a breach of a Basic Level. Occupational Levels applicable to adults in good health, with exposure generally limited to Exposure 8 hours/day Public Exposure Levels applicable to the general public without time-limit , including children and those in poor health or with devices such as pace makers implanted *. * Strictly, the sensitivity of pace makers or equivalent electronic devices should be confirmed with the manufacturer. The chosen Reference levels should not lead to problems with the great majority of devices.

Current Reference Level guidelines of NRPB for application in the UK are summarised in the following Table:

Table 2-2 – NRPB/ICNIRP Exposure Guidelines for EMF

Electric Field, kV/m Magnetic Flux Density, µT Frequency (Hz) (f=freq. in Hz) (f=freq. in Hz) Occup. Public Occup. Public 25 – 49 500/f 250/f 25,000/f 5000/f 50 10 5 500 100 51 – 800 500/f 25,000/f 5000/f 250/f 800 – 3000 0.61 30.7 6.25 3000 – 100,000 0.087

The new NRPB/ICNIRP proposals represent a substantial reduction on previous guidelines. vMainly this is simply as a result of increasing the safety margin between guidelines and any detectable physiological effects, combined with an increase in the margin between Basic and Reference levels. As a consequence it will be found in most instances that the presence of fields substantially in excess of Reference levels, will not result in the Basic levels expressed as current density in head or trunk being exceeded.

The NRPB recommendations for public exposure to electric and magnetic fields (which match the ICNIRP limits), are set out by the investigation levels for 50 Hz (shown in bold in Table 2-2): Electric Field strength 5 kV/m Magnetic Field strength 100 µT In situations where exposure may be described as occupational, higher limits apply, e.g. 10 kV/m and 500 µT for electric and magnetic fields respectively. This may be deemed to

9 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV apply to railway premises save for station platforms or other situations where there is public access.

Electric fields are calculated based on a nominal 25 kV AC rms voltage being applied to all catenary conductors. The actual voltage will vary with time and location, but with both normal and emergency feeding arrangements will remain below 27.5 kV (+10%) at almost all times.

Traction currents vary over a much wider band and short-time (in the order of one minute) peak traction currents could be up to twice the maximum ½-hourly mean values (the standard period for rating electrical equipment) which are used as the baseline. It is therefore desirable to allow for a substantial safety margin and a value in the order of 75 % of the appropriate guideline limit is applied for this assessment. There still remains a substantial conservative margin for error as design emergency feeder loads are taken as the basis of calculations.

(ii) Impact of Harmonic Currents

Traction currents are distorted, which is equivalent to being rich in higher harmonics. As shown in Table 2-2, the investigation or reference levels for both electric and magnetic fields fall with frequency, so there might be a theoretical risk that guidelines might be breached at higher harmonics.

In order to test this, a typical distorted current for an OLE supply is shown in Table 2-3 which may be used in the absence of better data. As can be seen, comparing the “content” column with the “Limit ∞ (proportional to) 1/f” column contents demonstrates that the typical maximum harmonic current magnitude is well below the limit implied by reducing the limit at fundamental frequency inversely to the harmonic number.

Table 2-3 Typical Traction Supply Harmonic Content

Harmonic Content Angle Limit ∞1/0066 1 100.00% 321 ° 100.0% 3 15.50% 268 ° 33.3% 5 7.60% 193 ° 20.0% 7 3.50% 109 ° 14.3% 9 1.40% 29 ° 11.1% 11 0.70% 310 ° 9.1% 13 0.50% 214 ° 7.7% 15 0.30% 110 ° 6.7% 17 0.15% 32 ° 5.9% 19 0.10% 296 ° 5.3% Source : Engineering Recommendation, page 24, Figure 14.

Even if Crossrail EMU’s have a higher harmonic content in their load currents, there is a substantial margin between magnetic field limits at harmonic frequencies and the probable harmonic levels.

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Typically, voltage distortion is less, expressed as a percentage, than current distortion at all harmonics.

(iii) Interference with Electronic Equipment.

Very much lower electrical and magnetic fields than the international guidelines for human safety can cause interference or mal-operation of sensitive equipment.

For guidance, fields in residential and commercial premises should be below about 3 A/m (≈4 µT) to avoid interference with, for example, VDU screens. NRPB recommendations cite values of 2 kV/m and 20µT as values below which interference with pace makers is unlikely to occur.

Electric fields can readily be shielded, and this will occur intrinsically within most typical buildings taking into account the “Faraday Cage” effect of wiring, piping, metal reinforcement etc, particularly in combination with the higher permittivity of common building materials. Magnetic fields cannot be shielded so readily, and assessment is best made assuming no shielding, whether indoors or out. It may also be mentioned that sources local to buildings (domestic apparatus and wiring) can give rise to fields of this magnitude, and any reported interference effects may well have causes other than the electrified railway.

(iv) Significance

Estimated field magnitudes which approach the guideline limits (see Section 2.4) are treated as significant in accordance with the following principles: • Significant if a guideline level is exceeded • Potentially significant if 75% of the guideline level is attained or exceeded • Not significant below 75% of the guideline level.

For clarity, the various limits to be considered are set out in Table 2-4.

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Table 2-4 – EMF Limits for Assessment

Basis of Limit Units Guideline Limit Potentially Significant Level (Occupational (Occupational Limit) Level)

Electric Fields, limit based on public health kV/m 5 3.75 considerations (NRPB) (10) (7.5) Magnetic Fields, limit based on public health µT 100 75 considerations (NRPB) (500) (375) Electric Fields, limit based on pace maker kV/m 2 1.5 interference (NRPB) Magnetic Fields, limit based on pace maker µT 20 15 interference (NRPB) EMC Recommendations (magnetic µT 4 3 interference with any electronic equipment

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3 Western Route Section

3.1 Methodology Used to Evaluate EMF Impacts Western Route The Great Western Main Line (GWML) is already electrified over the section from Paddington to Heathrow. The assessment has been based on developing and analysing a generic section of four-track main line built up by taking typical cross sections along the whole route, including both electrified and non-electrified portions of the GWML, as far as Maidenhead. This has enabled critical clearance distances from the railway to be identified. Ordnance Survey mapping was then reviewed to identify any approaches to buildings or sensitive locations closer than the critical distances. To confirm the findings of the assessment, fields at the boundaries of the sample sections were also calculated.

In general, minor variations in ground level were ignored and the calculations presume a level plane. If, in practice, there are significant level changes this will not have a major impact on the assessment. The electric and magnetic stresses immediately under the lines will be approximately the same in all cases, as the distance between ground plane and conductors does not vary. At a distance, the electric fields from an elevated track will be slightly greater, conversely if the track runs in a cut, they will be reduced.

The electric and magnetic fields along the length of the section were calculated using an in- house computer program "MELFP". Certain assumptions, mainly based on data provided for the Heathrow Express electrification were made, as summarised in Table 3-1.

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Table 3-1 Basic Assumptions made in assessing EMFs

Subject Assumption Catenary Two conductors each 11.68 mm diameter, at 4.73 and 4.95 m above ground level, directly above the mid-point between the running rails Return Conductor Single conductor 18.4 mm diameter on side of catenary support at 5 m above ground level and 2.25 m horizontally from the catenary Rail Notional conductor 100 mm diameter, with centre 0.18 m above ground level. Unless the rail is being used as a return conductor, its presence is ignored, as its affect on electric fields when installed so close to the ground, will be small. Similarly, and for the same reason, third (and fourth if LUL) conductor rails are ignored. Gauge Notionally 1.5 m, between centres of running rails. Platforms Nominal 1 m above ground level, platform edge set 1.5 m from track route centre-line. Catenary voltage All calculations are based on a nominal 25 kV 50 Hz voltage on the catenary. Catenary current Calculations are based on 200 A per main line catenary, each of which will have an assigned return conductor also carrying 200 A. The catenary over sidings is energised at 25 kV AC but does not carry current. It is referred to as a “catenary”, although in siding and depot areas it may be in the form of a simple trolley wire Magnetic fields are then scaled according to actual currents. See Section 3.3 below. Walls, buildings Electric fields will be modified by the presence of a building or wall, in general one or more notional earthed conductors 200 mm in diameter is placed along and up to the maximum height of the building or wall to represent the field attenuation resulting from an obstruction (which can be considered as conducting even if not metallic in construction) Magnetic fields are considered to be not affected by conventional building materials. Reference heights In open ground – 1.8 m, being head-height of an adult. On platforms, 2.8 m above ground level.

3.2 Typical Cross Section of Great Western Main Line

A total of nine cross sections of GWML were taken, each being as representative of locations with close approaches of housing or other buildings. From these measurements, a typical cross section was devised as illustrated below (dimensions are in metres):

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Figure 3-1 – Typical Section of GWML (4-track) after Electrification

An important factor in calculating the level of the magnetic field adjacent to the tracks is the location of the return conductors, and the proportion of the catenary current that flows in each return conductor,

It has been assumed that twin return conductors are provided at each end of the gantry supporting the catenaries. It is also assumed that booster transformers are installed to maximise the proportion of return current that flows in the return conductors.

Figure 3-2 – Field Plots for Typical GWML 4-track Section

Typical section GWML 4-track (Fields at head height, 1.8m)

4 32

3.5 28

3 24

2.5 20 Voltage field Magnetic field 2 16 Track_position Fences 1.5 12 VoltagekV/m25kV) (at Field Magnetic Field µT (at 20 MVA) 1 8

0.5 4

0 0 -25 -20 -15 -10 -5 0 5 10 15 20 25 m

The curves presented in Figure 3-2 presume each catenary is energised at 25 kV AC, and the total traction current is 800 A, or 20 MVA, with 100% current flowing in the return conductors. A sensitivity study with 95% current in the return conductors, the balance

15 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV through earth showed a small reduction in the magnetic fields close to the tracks offset by a small increase in the “far” fields, more than 30 m from the railway. The absolute magnitude of the magnetic fields at this distance is well below 1 µT, and has no significance (refer to Table 2-4).

3.3 Overhead Traction Power Supplies (25 kV AC)

The magnetic fields emanating from Crossrail overhead traction power supplies are proportional to the mean currents carried by the catenaries. Information as to the proposals for Crossrail and the total currents supplied from the various grid supply points has been provided by CLRLL.

The following figure is a schematic of the 25 kV AC traction power supplies, with peak ½-hour loads shown.

Figure 3-3 – Schematic of Power Supplies, West

For simplicity, the following assumptions are made: • Maximum catenary currents are equal to the ½ hour MVA loading of the supply feeder • The “1st Emergency” loading is taken as a design basis, any portion of the network could be supplied in this mode for an extended period, in the event of a major equipment breakdown. • Peak currents might be up to twice the average ½ hour MVA loading, so a safety margin of this magnitude should be sought between calculated magnetic field strengths and maximum permitted levels. This margin is provided after consideration of actual catenary currents compared to feeder loadings, as noted below.

In practice, catenary currents at all locations are likely to be significantly less than implied by the total feeder currents. For example, the normal maximum load from Iver towards Hanwell TSL is around 11 MVA, whereas for design purposes emergency feeder load of 17.6 MVA is

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In summary, the assessment has been based on adopting conservative assumptions where appropriate.

3.4 Findings from the Typical Section Of GWML

The electric and magnetic fields generated by the typical GWML section shown in Figure 3-2 are compared with guideline (potentially significant) limits shown in Table 2-4 to ascertain the zones of influence from the railway. Magnetic fields have been adjusted for peak catenary current 700 A, based on maximum ½-hour emergency feeder loading of 17.6 MVA (ex Slough/Iver).

Table 3-2 EMF on Typical GWML Section

Great Western Main Line Typical Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level 2.25m from fence line -2.25 0.37 3.75 3.0 75 Northern edge of land use 0 0.95 3.75 5.5 75 Track 1 C/L 6.25 2.62 7.5 18.7 375 Track 2 C/L 10 3.28 7.5 16.9 375 Track 3 C/L 13.75 3.27 7.5 16.9 375 Track 4 C/L 17.5 2.61 7.5 18.7 375 Southern edge of land use 23.75 0.67 3.75 5.5 75 2.25m from fence line 26 0.37 3.75 3.0 75 Note: Please refer to Table 2-2 for assessment levels. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

All EMF values are within both the latest guideline limits for public health issued by NRPB for Public and Occupational applications and the potentially significant levels (column 3 of Table 2-2) with the exception of electric and magnetic fields in open ground under the catenaries which may be of sufficient strength to affect pace makers.

Although the magnetic field is below the thresholds for the protection of public health, it exceeds the potentially significant level of 3 µT for possible interference with electronic equipment up to a distance of 2.25 m from the fence, or 8.5 m from the nearest electrified track (measured to track centre-line).

All personnel working on rail tracks are required to have a Personal Track Safety Certificate. This includes passing a medical examination to determine whether the worker exhibits any conditions likely to cause collapse on or near a line. General advice is given regarding a full range of medical conditions, including exposure to EMF, with particular safeguards provided to reflect the medical condition of the worker. Given these safeguards, the potential impact on workers fitted with pace makers is not considered significant.

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3.5 Modelling of GWML by Selected Sections

A number of actual cross sections along the GWML were selected for more detailed investigation where the actual conditions are significantly different from the typical cross section described above, either in terms of additional tracks or where there are buildings within 10 m of the nearest electrified (OLE) track identified. Note that properties with gardens where the end of the garden approaches closer than this distance were not included where the associated permanent buildings are at a greater distance.

3.5.1 Paddington Station to Old Oak Common Depot (Route Windows C2 to W3)

The results of calculating EMF levels are assessed with reference to the potentially significant levels below.

Table 3-3 EMF Results : Paddington Station to Old Oak Common Depot

Paddington Station to Old Oak Common Depot Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level Northern edge of land use 0 1.04 3.75 1.6 75 Track 1 C/L 6.25 2.67 7.5 4.7 375 Track 2 C/L 10 3.37 7.5 3.4 375 Track 3 C/L 13.75 3.42 7.5 1.4 375 Track 4 C/L 18.75 3.47 7.5 0.6 375 Track 5 C/L 22.5 3.54 7.5 1.4 375 Track 6 C/L 26.25 3.39 7.5 3.3 375 Track 7 C/L 30 2.70 7.5 4.7 375 Southern edge of land use 36.25 0.91 3.75 1.6 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The width of the reservation for the railway is substantial, and the traction currents are relatively light, based on a total of 190 A from Old Oak No. 2 Feeder Station. As a consequence, all EMF values are within both the guideline and potentially significant limits with the exception of electric fields in open ground under the catenaries which may be of sufficient strength to affect pace makers.

The magnetic field is within the potentially significant level of 3 µT for possible interference with electronic equipment at both the northern and southern edges of land use.

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3.5.2 Ealing Broadway Station to West Ealing Station (Route Window W5 – W6)

The results of calculating EMF levels are assessed with reference to the potentially significant levels below.

Table 3-4 EMF Results: Ealing Broadway Station to West Ealing Station

Ealing Broadway Station to West Ealing Station Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level Northern edge of land use 0 0.28 3.75 0.6 75 Track 1 C/L 17.5 2.56 7.5 18.1 375 Track 2 C/L 21.25 3.02 7.5 14.4 375 Track 3 C/L 27.5 3.02 7.5 14.4 375 Track 4 C/L 31.25 2.57 7.5 18.1 375 Southern edge of land use 43.75 0.32 3.75 1.4 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The magnetic field is within the potentially significant level of 3 µT for possible interference with electronic equipment at both the northern and southern edges of land use.

3.5.3 Hayes & Harlington Station to Stockley Flyover (Route Window W10 – W11)

The chosen section has a total of seven tracks, and it is assumed that traction current is predominantly being carried on the outer four catenaries, to provide a conservative assessment. The railway boundaries, indicated by fence positions on the sketch shown below, are close to the gantry supports, particularly on the northern boundary:

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Figure 3-4 –Section Diagram

The resulting electric and magnetic fields are summarised in the following table, along with the estimated positions at which the magnetic field falls to 3µT, the potentially significant level for interference with electronic equipment.

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Table 3-5 EMF Results : Hayes & Harlington Station to Stockley Flyover

Hayes and Harlington Station to Stockley Flyover Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level 5.5 m from fence line -5.5 0.43 3.75 2.9 75 Northern edge of land use 0 1.66 3.75 12.3 75 Track 1 C/L 3.75 2.66 7.5 17.1 375 Track 2 C/L 7.5 3.34 7.5 12.2 375 Track 3 C/L 11.25 3.40 7.5 5.0 375 Track 4 C/L 16.25 3.32 7.5 1.9 375 Track 5 C/L 21.25 3.40 7.5 5.0 375 Track 6 C/L 25 3.36 7.5 12.3 375 Track 7 C/L 28.75 2.67 7.5 17.1 375 Southern edge of land use 33.75 0.88 3.75 8.7 75 4.5 m from fence line 38.25 0.41 3.75 2.8 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

Although the magnetic field is below the thresholds for the protection of public health, it exceeds the potentially significant level of 3 µT for possible interference with electronic equipment up to a distance of 5.5 m beyond the northern fence line and 4.5 m beyond the southern fence line.

3.5.4 Stockley Flyover to West Drayton Station (Route Window W11 – W13)

As shown in the following Figure, the railway is very close to its northern boundary fence, and the fields at this location are expected to be significant.

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Figure 3-5 – Section Diagram

The calculated electric and magnetic fields at this section are summarised in the following table:

Table 3-6 EMF Results: Stockley Flyover to West Drayton Station

Stockley Flyover to West Drayton Station Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level 4.5 m from fence line -4.5 0.41 3.75 3.0 75 Northern edge of land use 0 1.58 3.75 11.9 75 Track 1 C/L 3.75 2.60 7.5 19.0 375 Track 2 C/L 7.5 3.22 7.5 17.1 375 Track 3 C/L 11.25 3.06 7.5 16.2 375 Track 4 C/L 18.75 2.20 7.5 16.2 375 Southern edge of land use 43.75 0.12 3.75 0.4 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

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3.5.5 Iver Station to Langley Station (Route Window W14 – W16)

Table 3-7 EMF Results: Iver Station to Langley Station

Iver Station to Langley Station Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level Northern edge of land use 0 0.50 3.75 1.6 75 Track 1 C/L 11.25 2.62 7.5 18.9 375 Track 2 C/L 15 3.27 7.5 17.0 375 Track 3 C/L 18.75 3.19 7.5 16.5 375 Track 4 C/L 23.75 2.44 7.5 17.7 375 Southern edge of land use 32.5 0.48 3.75 3.1 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The width of the railway reservation is sufficient for all electric and magnetic fields to fall within both the guideline limits for public health and the potentially significant levels with the exception of electric and magnetic fields in open ground under the catenaries which may be of sufficient strength to affect pace makers.

The magnetic field is within the potentially significant level of 3 µT for possible interference with electronic equipment at both the northern and southern edges of land use.

3.5.6 Langley Station to Slough Station (Route Window W16 – W18)

As shown in the following Figure, the railway is very close to its southern boundary fence, and the fields at this location are expected to be significant.

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Figure 3-6 – Sheet 333, Section Diagram

The calculated electric and magnetic fields at this section are summarised in the following table:

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Table 3-8 EMF Results : Langley Station to Slough Station

Langley Station to Slough Station Electric field (kV/m) Magnetic field (µT) Feature Distance Calculated Potentially Calculated Potentially across Significant Significant section (m) Level Level Northern edge of land use 0 0.50 3.75 1.6 75 Track 1 C/L 11.25 2.62 7.5 18.9 375 Track 2 C/L 15 3.27 7.5 17.0 375 Track 3 C/L 18.75 3.19 7.5 16.5 375 Track 4 C/L 23.75 2.44 7.5 17.7 375 Southern edge of land use 32.5 0.48 3.75 3.1 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

All EMF values are within both the latest guideline limits for public health issued by NRPB for Public and Occupational applications and the potentially significant levels with the exception of electric and magnetic fields in open ground under the catenaries which may be of sufficient strength to affect pace makers.

3.5.7 Slough Station to Burnham Station (Route Window W18 – W21)

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Table 3-9 EMF Results : Slough Station to Burnham Station

Electric field (kV/m) Magnetic field (µT) Slough Station to Distance Calculated Potentially Calculated Potentially Burnham Station across Significant Significant section (m) Level Level Northern edge of land use 0 0.50 3.75 1.6 75 Track 1 C/L 11.25 2.62 7.5 18.9 375 Track 2 C/L 15 3.27 7.5 17.0 375 Track 3 C/L 18.75 3.19 7.5 16.5 375 Track 4 C/L 23.75 2.44 7.5 17.7 375 Southern edge of land use 33.75 0.41 3.75 2.4 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The magnetic field is within the potentially significant level of 3 µT for possible interference with electronic equipment at both the northern and southern edges of land use.

3.5.8 Burnham Station to Taplow Station (Route Window W21 – W23)

As shown in the following Figure, the fence is closer than 8.5 m to the southernmost electrified track, and the fields at this location are expected to be significant.

Figure 3-7 – Section Diagram

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The calculated electric and magnetic fields at this section are summarised in the following table:

Table 3-10 EMF Results : Burnham Station to Taplow Station

Electric field (kV/m) Magnetic field (µT) Burnham Station to Distance Calculated Potentially Calculated Potentially Taplow Station across Significant Significant section (m) Level Level Northern edge of land use 0 0.50 3.75 1.6 75 Track 1 C/L 11.25 2.62 7.5 18.9 375 Track 2 C/L 15 3.27 7.5 17.0 375 Track 3 C/L 18.75 3.18 7.5 16.5 375 Track 4 C/L 23.75 2.44 7.5 17.7 375 Southern edge of land use 30 0.91 3.75 5.9 75 3 m from fenceline 33 0.34 3.75 2.8 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

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3.5.9 Taplow to Maidenhead (Route Window W23 – W25)

Table 3-11 EMF Results : Taplow to Maidenhead

Electric field (kV/m) Magnetic field (µT) Taplow to Distance Calculated Potentially Calculated Potentially Maidenhead across Significant Significant section (m) Level Level Northern edge of land use 0 0.21 3.75 0.3 75 Track 1 C/L 21.25 2.63 7.5 18.7 375 Track 2 C/L 25 3.29 7.5 16.9 375 Track 3 C/L 28.75 3.28 7.5 16.9 375 Track 4 C/L 32.5 2.62 7.5 18.7 375 Southern edge of land use 53.75 0.16 3.75 0.3 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards

The width of the railway reservation is sufficient for all electric and magnetic fields to fall within both the guideline limits for public health and the potentially significant levels with the e exception of electric and magnetic fields in open ground under the catenaries which may be of sufficient strength to affect pace makers.

The magnetic field is within the potentially significant level of 3 µT for possible interference with electronic equipment at both the northern and southern edges of land use.

3.6 Summary of EMF Impacts along GWML Paddington to Maidenhead

This study has estimated the electric and magnetic fields for a range of cross-sections representative of the route of the GWML from Paddington to Maidenhead. Traction loads are based on the proposed Crossrail service to both Heathrow and Maidenhead and incorporating the other services that would be operating on those routes sections.

The results are summarised in Table 3-12.

3.6.1 Protection of Public Health

The electric and magnetic field strengths are all calculated to be below the potentially significant level for the protection of public health at the fenceline.

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3.6.2 Protection of Occupational Health

The electric and magnetic field strengths are all calculated to be below the potentially significant level for the protection of occupational health at the fenceline. There are some sections where electric and magnetic field strengths directly beneath the catenaries will be above the significance level for interfering with pace makers. All personnel working on rail tracks are required to have a Personal Track Safety Certificate. This includes passing a medical examination to determine whether the worker exhibits any conditions likely to cause collapse on or near a line. General advice is given regarding a full range of medical conditions, including exposure to EMF, with particular safeguards provided to reflect the medical condition of the worker. Given these safeguards, the potential impact on workers fitted with pace makers is not considered significant.

3.6.3 Interference with Electronic Equipment

The magnetic field strengths are calculated to be within the potentially significant level for interference with electronic equipment generally within the rail fenceline and, in all circumstances, within 5.5 m outside the fenceline. The conservative assumptions made in calculating magnetic field strengths, the rapid decay in field strengths with distance from the source and the designation of a significance level at 75 % of the published threshold suggests there the potential for interference with electronic equipment is not significant.

3.6.4 Summary

The results confirm that a separation of 10 metres or less from the nearest electrified track is required to reduce the electric and magnetic fields to below potentially significant levels. The calculations indicate that all assessment criteria will be achieved with the exception of potential interference with pace makers if worn by workers underneath the catenaries. All personnel working on rail tracks are required to have a Personal Track Safety Certificate. This includes passing a medical examination to determine whether the worker exhibits any conditions likely to cause collapse on or near a line. General advice is given regarding a full range of medical conditions, including exposure to EMF, with particular safeguards provided to reflect the medical condition of the worker. Given these safeguards, the potential impact on workers fitted with pace makers is not considered significant.

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Table 3-12 Summary of EMF Levels from Typical and Representative Crossrail Track Sections at the Nearest Railway Boundaries

Magnetic Field µT Electric Field kV/m Potentially Potentially Location where no Significant Significant interference with Level Level electronic equipment At nearest Public Pace At nearest Public Pace would occur Cross Section Fenceline Health maker Fenceline Health maker (< 3µT) Typical 0.9 3.75 1.5 5.5 75 15 Within rail fenceline Paddington 1.0 3.75 1.5 1.6 75 15 Within rail fenceline Station to Old Oak Common Depot Ealing 0.3 3.75 1.5 1.4 75 15 Within rail fenceline Broadway Station to West Ealing Station Hayes & 1.7 3.75 1.5 12 75 15 5.5 m beyond the Harlington fenceline Station to Stockley Flyover Stockley 1.6 3.75 1.5 12 75 15 4.5 m beyond the Flyover to West fenceline Drayton Station Iver Station to 0.5 3.75 1.5 3.1 75 15 Within rail fenceline Langley Station Langley Station 1.5 3.75 1.5 12 75 15 5.5 m beyond the to Slough fenceline Station Slough Station 0.5 3.75 1.5 2.4 75 15 Within rail fenceline to Burnham Station Burnham 0.9 3.75 1.5 5.9 75 15 3 m beyond the Station to fenceline Taplow Station Taplow to 0.2 3.75 1.5 0.3 75 15 Within rail fenceline Maidenhead Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards

3.7 Buildings Where Magnetic Field Strengths Exceed Interference Levels

Studies of the EMF generated by the upgrading and construction of overhead traction power supplies for proposed Crossrail services, taking into account the “pessimistic-case” loadings

30 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV identified in section 3.3, have established the critical distances from electrified track required to comply with requirements in accordance with safety and interference guidelines for electrical and electronic equipment.

For the purposes of identifying locations which might be subjected to magnetic field levels in excess of 3 µT, the “potentially significant” levels for interference with electronic equipment, Ordnance Survey maps of the GWML route from Paddington to Maidenhead were reviewed to identify buildings that are situated within 9-10 m of an electrified track (measured to track centre-line). The locations noted which fall into this category are identified in Table 3-13. Note that none of the properties is expected to contain electronic equipment of sufficient sensitivity to magnetic fields at the strengths calculated at these locations.

Table 3-13 – Buildings within 10 m of GWML Electrified Tracks

Route Address Potential for Interference with Window Electronic Equipment Buildings currently next to electrified track Outbuilding adjacent to St Thomas No equipment of sufficient sensitivity CE Primary School expected to be present. 38 Golborne Road No equipment of sufficient sensitivity expected to be present. 25 Hanger Lane No equipment of sufficient sensitivity expected to be present. Villiers House Building above existing HEX electrified tracks at Ealing Broadway station. No equipment of sufficient sensitivity expected to be present. West Ealing Business Centre, Units No equipment of sufficient sensitivity 1a, 2a, 2d and 3a expected to be present.

Dawley Road (two large trackside Purpose unknown, possibly Railway buildings by Bournes Bridge) buildings.

The following entries are beyond Stockley Flyover and are therefore next to non-electrified track at present. 323/4 Works, by Horton Bridge on Grand No equipment of sufficient sensitivity Union Canal expected to be present. 324 The De Burgh Arms Hotel No equipment of sufficient sensitivity expected to be present. 333 Trackside building between Australia Purpose unknown, possibly Railway and Canada Roads buildings.

334 Industrial building to NE of Slough No equipment of sufficient sensitivity Station expected to be present.

343 Premises on River Road, just north of No equipment of sufficient sensitivity GWML river bridge expected to be present.

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4 Central Route Section

4.1 Extent of Study

This section considers the central tunnelled sections of Crossrail between Royal Oak Portal and Pudding Mill Lane Portal/Isle of Dogs Station, as described in Volume I.

4.2 Methodology

The basis of the tunnel model is a 25kV electrification within all the proposed Crossrail tunnel sections using a proprietary (nominally the Furer+Frey type) overhead conductor rail (contact beam) with multiple earth wire provision (i.e. no return conductors and booster transformers) located in the tunnel soffit in close proximity to the conductor rail.

The “multiple earth wire provision” is modelled by separating out the return currents and the remaining current which enters the earth. Note the absence of booster transformers means that return current is not “forced” onto the return conductors as it is on the surface railway. Most of the current will flow down the path of much lower reactance between catenary and return conductors in the tunnel roof, but a proportion will flow in earth.

Figure 4-1 shows the assumed tunnel section, showing return conductors in the roof of the tunnel, close to the contact wire (beam) and running rails. The clearance between contact wire and running rails is 4.2 m. The return conductors are located a nominal 0.5 m above the contact wire. The tunnel walls are presumed to be reinforced concrete segments and their conductivity and magnetic properties may be ignored.

33 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV

Figure 4-1 – Typical Tunnel Section

4.2.1 Load Currents

The AC Feeder Station Loadings for the central tunnel section assumed for this study are presented in Table 4-1.

Table 4-1 – Central Area Traction Loads

Supply point incoming Maximum ‘half Maximum one Maximum ‘half Maximum one circuit hour average’ minute Peak hour average’ minute Peak MVA (Normal) Current (A) MVA Current (A) (Normal) (1st emerg’) (1st emerg’) Willesden F4 ------26.9 1836 (Westbourne Park) ’Hot-standby’ ’Hot-standby’ without S. Green ------25.2 1709 ’Hot-standby’ ’Hot-standby’ to S. Green only West Ham F5 (Custom 25.8 1778 3.9 234 House) without S. Green to Bow & Custom House 3.9 234 25.8 1778 with S. Green without S. Green Source: CLRLL. The load currents in the catenaries are taken as the mean 1-minute Peak value of 1800A, normally divided 50:50 between each tunnel. The case when one tunnel carries 100% of the load is also tested in some circumstances.

For the purposes of estimating magnetic fields it was assumed that the maximum current flows in the catenary, whether supplied from Willesden, Stepney Green or Custom House, without allowance for load current attenuation along the route of the tunnel.

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4.2.2 Earth Currents

The external magnetic fields in locations remote from the tunnels are heavily influenced by the proportion of catenary current that flows through earth.

Without booster transformers, the current flows are determined by the relative impedances of the paths via the running rails and return conductors and earth. The return conductors will present a relatively low reactance path in comparison with the loop reactance with earth return. Moreover, the close mutual coupling between the catenary and its return conductors (both with earth return) will further reduce earth currents since load current will induce a voltage into the return conductors such as to force a higher proportion of return current into them.

The proportion of current that flows in the earth will be a function of the resistance of the return conductors, their disposition relative to the catenary, the point or points at which they are earthed and the resistance of those earth connections. For assessing the likely magnitude of this current the resistance of the return conductors is expected to be in the order of 0.025 ohms/km, compared to an earth loop impedance which may be about 0.5 ohms/km. Hence approximately 5% of catenary current may return via earth.

In view of the uncertainty in this estimate, a sensitivity study was also carried out presuming 10% of total load current returns through earth.

The phase angle of earth fault current relative to catenary current will vary according to the electrical characteristics of the return circuits. Both the 0° and 90° extremes were tested, and the worst case selected.

4.3 Magnetic Fields at Susceptible Properties

The data on the height of the lowest floor in each building, rail heights above datum and separations to West and Eastbound tunnels enables the magnetic fields in the building basements or ground floor levels to be calculated, with the tunnel modelling, catenary and earth currents as stated in the generic modelling of the central area.

When checking the initial results, some unusually low magnetic field strengths were recorded in some locations, generally those with a building between the two Crossrail tunnels. This was due to the building being close to a “null” location in the complex field patterns generated by a number of current-carrying conductors. In these cases, modelling catenary currents as the same in each tunnel leads to the creating of null points. Selected studies were repeated with identical conditions save that the catenary current in one tunnel (the furthest away) was reduced to zero, and increased in the nearer tunnel to 100% of the peak value. Earth and return currents were similarly modified.

This approach is onerous, but more indicative of real conditions when there could be a substantial disparity in the currents in the two tunnels. When the magnetic fields result from what is effectively the sum of the currents, allocation of current to each tunnel may be arbitrary. However in the identified cases, the fields generated by some conductors cancel when they are of similar magnitude, hence the change of model.

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4.4 Susceptible Properties – Maximum Fields with 5% Earth Current

This study has used building obstructions data provided by CLRLL (compiled when developing and designing the tunnels alignments) and land use information to identify buildings that might be sensitive to EMF emissions from the tunnel sections.

The magnetic fields in the great majority of the buildings identified as potentially susceptible with stray earth fault current 5% of catenary, current fall below 1.0 µT. If the data is regarded as having a Normal distribution, an estimate can be made of the maximum field in any property close to the Crossrail tunnels as shown in Table 4-2.

Table 4-2 - Fields with 5% Earth Current

Fields with 5% Earth Current µT Min 0.11 Mean 0.49 Max 1.14 Standard Deviation 0.20 Max to 99.5% confidence level 0.99

A maximum level of 1 µT may be expected in any property near Crossrail tunnels with a 99.5% confidence level, based on the most probable case of 5% of catenary load current flowing through earth.

This result may be compared with the maximum field levels at the surface found when testing a range of generic models. The maximum field strength when considering specific properties is greater, principally because of the closer approach to building basements below ground level to the running tunnels. However, the magnetic field strengths are well below the potentially significant levels for interference with pace makers or electronic equipment.

4.5 Susceptible Properties – Maximum Fields with 10% Earth Current

As for the studies of generic models, the fields are measured with a higher value of stray earth fault current, up to 10% of maximum catenary current.

The magnetic fields with stray earth fault current 10% of catenary current fall below 2.0 µT in the great majority of the buildings. An estimate can be made of the maximum field in any property close to the Crossrail tunnels as shown in Table 4-3. The magnetic field strengths are well below the potentially significant levels for interference with pace makers or electronic equipment.

36 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV

Table 4-3 - Fields with 10% Earth Current

Fields with 10% Earth Current µT Min 0.22 Mean 0.92 Max 2.07 Standard Deviation 0.34 Max to 99.5% confidence level 1.80

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5 Eastern Route Section

5.1 Extent of Study

This section considers the works in the north east route section from Pudding Mill Lane Portal to Shenfield Station and the sourth east, from Isle of Dogs Station to Abbey Wood Station, the south east section, respectively.

5.2 Crossrail Service on Existing 25 kV AC Electrified Railway

The route from the tunnel portal at Pudding Mill Lane to Shenfield Station makes use in the most part of existing 25 kV AC electrified lines from Liverpool Street to Colchester and Southend.

Where Crossrail services run over existing 25 kV overhead (OLE) electrified track, there will be no impact on EMFs, save for an increase or decrease in magnetic fields if total catenary current changes from present levels.

5.3 Crossrail Service on Existing 750 V DC Electrified Railway

Crossrail would extend the OLE from Custom House Station to Abbey Wood via the Connaught and Thames tunnels.

The power supply arrangements for this extension are assumed to be fed from the Custom House feeder (see central Section) with a TSL at Abbey Wood.

5.4 New Alignments Necessitated by Crossrail Works

Six locations have been identified which would have new or modified alignments.

(i) Pudding Mill Lane

The Crossrail tracks emerge from the tunnel portal to the west of Pudding Mill Lane and join the existing 25 kV AC tracks from Liverpool Street to Shenfield. This will require the prior realignment of Docklands Light Railway (DLR) tracks and a new DLR station.

(ii) Gidea Park Sidings

New Crossrail sidings will be constructed at Gidea Park, bringing electrified tracks closer to existing properties on the north side.

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(iii) Shenfield Station and Sidings

New alignments and sidings are proposed at Shenfield, although these will be accommodated between existing electrified tracks, and will have only a small effect at the boundaries of railway property.

(iv) Custom House

The Crossrail tracks (powered at 25 kV AC overhead catenary) emerge from the southern tunnel portal. The North London and DLR tracks will be re-aligned.

(v) Romford Depot

Land will be taken from the gas works on the south side of the existing Great Eastern Main Lines (GEML), and electrified tracks installed to the depot building and train stabling facilities at the eastern end of the site. New alignments approach housing on the north side prior to passing under the existing GEML. Thereafter, new alignments approach housing on the south side.

The whole Romford site is dedicated to Railway purposes, with no access to the general public or passengers. EMF consideration are limited to those pertaining at the site boundaries, although the data from modelling within the site is also provided.

(vi) Custom House to Abbey Wood

Crossrail services take over the North London Line alignment at Custom House and be extended to Abbey Wood via a new tunnel under the Thames, from North Woolwich to Plumstead. Existing services north and south of the river use 750 V DC traction power supplies, but it is proposed to convert these portions of the route to 25 kV AC overhead, with the benefit of permitting Crossrail stock to be suitable for single power supplies.

Apart from the new Thames tunnel, Crossrail services will run on the existing alignment. However the change to overhead traction power supplies requires that EMFs are evaluated along this route.

5.5 Prediction of Impacts

5.6 Methodology

The same methodology was adopted as described in Section 3.1 for the western route section. Certain assumptions, mainly based on data provided for the Heathrow Express electrification are made, which are summarised in the following Table.

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Table 5-1 Basic Assumptions made in assessing EMFs

Subject Assumption Catenary Two conductors each 11.68 mm diameter, at 4.73 and 4.95 m above ground level, directly above the mid-point between the running rails Return Conductor Single conductor 18.4 mm diameter on side of catenary support at 5 m above ground level and 2.5 m horizontally from the catenary Rail Notional conductor 100 mm diameter, with centre 0.18 m above ground level. Unless the rail is being used as a return conductor, its presence is ignored, as its affect on electric fields when installed so close to the ground, will be small. Similarly, and for the same reason, third (and fourth if LUL) conductor rails are ignored. Gauge Notionally 1.5 m, between centres of running rails. Platforms Nominal 1 m above ground level, platform edge set 1.5 m from track route centre-line. Catenary voltage All calculations are based on a nominal 25 kV 50 Hz voltage on the catenary. Catenary current Calculations are based on 200 A per main line catenary, each of which will have an assigned return conductor also carrying 200 A. The catenary over sidings is energised at 25 kV AC but does not carry current. It is referred to as a “catenary”, although in siding and depot areas it may be in the form of a simple trolley wire Magnetic fields are then scaled according to actual currents. See Section 3.3 above. Power Line Applicable at Custom House, see discussion of EMF impacts at dimensions, voltages this location. and currents Walls, buildings Electric fields will be modified by the presence of a building or wall, in general a notional earthed conductor 200 mm in diameter is placed at the maximum height of the building or wall to represent the field attenuation resulting from an obstruction (which can be considered as conducting even if not metallic in construction) Magnetic fields are considered to be not affected by conventional building materials. Reference heights In open ground – 1.8 m, being head-height of an adult. On platforms, 2.8 m above ground level.

An illustration of a twin-track main line is shown in the following Figure, using the dimensions listed above:

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Figure 5-1 – Typical Section of Main line Twin-track

An important factor in calculating the level of the magnetic field adjacent to the tracks is whether the return current flows through the high-level return conductor or through the running rails. In practice if a train or locomotive is drawing current in the immediate locality, a proportion of the catenary current will flow through the rail. The presence of booster transformers ensures that most of the total current will pass in the return conductor.

To demonstrate this effect, two magnetic field plots are shown on the graph below, the higher (peaking at 48.9 µT) results from 100% of the catenary current (400 A in this case) returning through two of the running rails, the lower (11.1 µT) when all the catenary current, also 400 A, returns through the two return conductors. The voltage field is also plotted.

42 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV

Figure 5-2 – Field Plots for Twin Track 25kV Electrified Railway

Typical twin-track EMFs, measured at 1.8 m above ground level

3 90 2.70 kV/m

2.5 75

2 60

48.9 uT

1.5 45 Magnetic Field uT Field Magnetic Electric Field kV/m Field Electric 1 30

0.5 11.1 uT 15

0 0 -15 -10 -5 0 5 10 15 metres

kV/m uT (return conductor) uT (rail)

In general the studies of actual cross-sections on the surface Crossrail routes equipped with booster transformers will be based on the assumption that the total current returns via return conductors. In practice, there will be some temporary increase in the local magnetic field as a train passes through the locations in question, but it will be much less than suggested by the above graph, since only a fraction of total catenary current will return via the rails.

5.7 Crossrail Central & Eastern Power Supplies (25 kV AC)

The data are summarised in the following diagram, with one important exception. A new feeder substation is proposed at West Ilford to overcome possible problems with the degree of unbalance on grid supplies. The case for this reinforcement is marginal, and may be avoided if Grid fault levels can be increased at modest cost, or detailed investigations show an acceptable maximum imbalance between phases. If West Ilford is not installed, catenary currents will be higher than otherwise, hence this represents a worst case.

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Figure 5-3 – Schematic of Power Supplies, Central and East OLE

A neutral section between Bow and Crowlands has been inserted in place of West Ilford.

For simplicity, the following assumptions were made: • Maximum catenary currents are equal to the ½ hour MVA loading of the supply feeder • The “1st Emergency” loading is taken as a design basis, any portion of the network could be supplied in this mode for an extended period, in the event of a major equipment breakdown. • Peak currents might be up to twice the average ½ hour MVA loading, so a safety margin of this magnitude should be sought between calculated magnetic field strengths and maximum permitted levels.

In practice, catenary currents at all locations are likely to be significantly less than implied by the total feeder currents.

The proposal assessed for this study is for isolation transformers at Custom House to power the section where a change-over to DC traction occurs.

It has been assumed that the power supplies will be required for predicted traffic of 12 t.p.h.d. and the catenary current at the supply point will be in the order of 10 MVA. This corresponds to a peak 1-minute current of less than 800 A (total), so this value is used for reference in the studies of EMFs.

5.8 Window C13 – Pudding Mill Lane

5.8.1 Choice of Section

Crossrail tracks emerge from the Pudding Mill Lane portal and pass through a cut and cover emerging north of a new Docklands Light Rail station, where they join the main line from Liverpool Street to Shenfield.

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A new "Up Electric Loop" is provided to the south of the new Crossrail line, which passes at its closest approach to the west end of the DLR platforms. This location is chosen for the section, as illustrated in Figure 5-4.

At this point (Chainage approximately 14550.000) the elevation of Crossrail track and existing 25 kV main line is the same ±0.5 m, so both Crossrail tracks, the "Up Electric Loop" and DLR tracks are represented, as it is assumed that Crossrail is no longer shielded by the cut. Modelling commences with the "Down Electric Loop" southwards, there is no change to tracks (including LUL) north of this position.

Figure 5-4 – Pudding Mill Lane - Map

Transport for London

The section details at Pudding Mill Lane are shown below. Note the tracks scheduled for removal, in the modelling these are not energised.

Fields are assessed at heights of 1.8 and 2.8 m, representing passengers on the DLR station platforms.

Figure 5-5 – Pudding Mill Lane – Plan

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5.8.2 Pudding Mill Lane – Results

Total currents in the catenary were taken as 580 A, the base current as 800 A and hence a factor of 0.725 was applied to generate the tabulated magnetic field values.

Table 5-2 – Pudding Mill Lane EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level Down Electric Loop 2.0 7.5 5.8 375 Crossrail 2.8 7.5 8.1 375 Up Electric Loop 2.1 7.5 6.3 375 Down Docklands platform (N) 0.88 3.75 6.2 75 Down Docklands platform (S) 0.40 3.75 1.3 75 Up Docklands platform (N) 0.19 3.75 0.36 75 Up Docklands platform (S) 0.13 3.75 0.22 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Electric and magnetic fields will be less than the potentially significant level expected to interfere with pace makers (1.5 kV/m and 15µT, respectively) in locations of public access but may be of sufficient strength to affect pace makers if people are working directly beneath the catenaries.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.9 Window NE11 – Gidea Park Sidings

5.9.1 Choice of Section (1)

At Gidea Park existing sidings are being extended for Crossrail rolling stock, and will extend further north. Two sections are chosen, the first at the re-alignment at the turn-out to the sidings, where the tracks pass close to property Robert Falcon Scott Lodge, behind a 4 m retaining wall.

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This section is illustrated in Figure 5-6

Figure 5-6 – Gidea Park Sidings Map (Section 1)

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Figure 5-7 - Gidea Park Sidings – Plan, Section 1

5.9.2 Gidea Park Sidings (Section 1) – Results.

Total currents in the catenary taken as 630 A, base current for study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

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Table 5-3 – Gidea Park Sidings (Section 1) EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level Robert Falcon Scott Lodge 0.14 3.75 0.24 75 Turnout to Crossrail Sidings 2.2 7.5 0.95 375 Down Electric 2.2 7.5 6.1 375 Signal Box (N) 1.0 7.5 6.0 375 Signal Box (S) 1.0 7.5 8.4 375 Up Electric/Up Main 3.2 7.5 16.7 375 Siding 2.3 7.5 8.0 375 Warehouse north wall (8m S 0.6 3.75 1.5 75 of siding) Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.9.3 Choice of Section (2)

The second section is where the sidings are at their maximum extent northwards, south of Evelyn Sharp House.

This section is illustrated in Figure 5-8

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Figure 5-8 – Gidea Park Sidings Map (Section 2)

Transport for London

Figure 5-9 - Gidea Park Sidings – Plan, Section 2

5.9.4 Gidea Park Sidings (Section 2) – Results.

Total currents in the catenary taken as 630 A, base current for study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

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Table 5-4 – Gidea Park Sidings (Section 2) EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level Evelyn Sharp House 0.25 3.75 0.17 75 Crossrail new sidings 3.6 7.5 9.7 375 Down Electric 2.7 7.5 8.3 375 New Siding 2.6 7.5 7.4 375 Up Electric-Existing siding 3.4 7.5 14.5 375 Residential 12 m S of siding 0.25 3.75 0.57 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.10 Window NE17 – Shenfield Station

5.10.1 Choice of Section

New sidings are proposed for Shenfield, with re-alignments. The Southend Loop gradually diverges from the main line until crossing over it, hence the greatest EMFs will arise before this divergence is significant, but after the sidings start. A section was selected south of No. 97 Hunter Avenue, as shown in Figure 5-10

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Figure 5-10 – Shenfield Sidings Map

Transport for London

Figure 5-11 – Shenfield Sidings – Plan

5.10.2 Shenfield Sidings – Results.

Total currents in the catenary taken as 450 A, base current for study was 1200 A, hence a factor of 0.375 has been applied to generate the tabulated magnetic field values.

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Table 5-5 – Shenfield Sidings – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level Rear of 97 Hunter Av. 0.06 3.75 0.11 75 (House) Rear of 97 Hunter Av. 0.4 3.75 0.24 75 (Garden) Southend Loop 2.3 7.5 3.0 375 Crossrail Sidings 3.2 7.5 1.5 375 Chelmsford Loop 2.8 7.5 7.9 375 Main Lines 3.2 7.5 4.9 375 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.11 Window SE2 – Custom House

5.11.1 Choice of Section (1)

Crossrail tracks emerge from the tunnel portal to the west of the Custom House station, using the North London line alignment.

This station is provided with both 25 kV overhead and 750 V DC traction power supplies.

An electricity overhead line is constructed on pylons paralleling the route, just to the south of Custom House station. Reference to NGC maps indicates that this line as being operated at 275 kV (159 kV line-earth) and 500 A per circuit and this has been assumed for the purposes of assessing its impact on EMFs at Custom House Station.

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The first Section chosen at Custom House is at the end of the Crossrail open cut, just after Crossrail and North London line tracks have merged. This is also approximately mid-span on the electricity overhead line, hence the point with the lowest ground clearance.

This section is illustrated in Figure 5-12

Figure 5-12 – Custom House Map (Section 1)

Transport for London

© CROWN COPYRIGHT. ALL RIGHTS RESERVED' (GLA - 100032379) (2005) The section plan is shown in Figure 5-13 below. Note that the lower conductors of the overhead line (which is presumed to be of double-circuit construction, as this is most common in the UK) will sag to minimum ground clearance at around this point. As a guide as to what that clearance might be, recommended minimum clearances are taken from publication EA 43–8 “Overhead Line Clearances”, Table 4, which refers specifically to railway clearances. It is probable that mobile crane access would be required on the south side of the station, and the required minimum clearance for railway ground which may be used by mobile cranes is 11.5 m, for 275 kV overhead lines.

This value would also permit single-storey buildings on the station platforms which require 4.6 m clearance to the building’s roof, at worst-case swing angle of the power conductors. Approximately, a building up to 6 m height (say 5 m above platform level) could be present.

The purpose of this analysis is to establish a baseline for EMF calculations. The details provided above are for reference only, and detail designs would need to be approved by the appropriate authorities as per normal procedures.

Phase conductors are presumed to be twin Zebra ACSR. Phasing of the nearest conductor is assumed to be the same as Crossrail traction power supplies. Phase rotation is reversed on the adjacent circuit, this being common practice.

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Figure 5-13 – Custom House – Plan, Section 1

5.11.2 Custom House (Section 1) – Results.

Total currents in the catenary taken as either 400 A or 0 A. The tabulated magnetic field values, which arise from a combination of railway traction current and electricity authority power line, are shown separately.

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Table 5-6 – Custom House (Section 1) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant 400 A 0 A Level Level Victoria Dock Road C/L 0.21 7.5 0.95 0.37 375 Wall 0.37 7.5 5.8 0.51 375 Crossrail Eastbound 2.0 7.5 9.1 0.66 375 Crossrail platform (N edge) 2.3 3.75 8.7 0.75 75 Crossrail platform (S edge) 2.4 3.75 9.2 1.4 75 Crossrail Westbound 2.2 7.5 8.1 1.5 375 Wall 1.3 3.75 5.2 2.1 75 DLR platform (N edge) 1.9 3.75 3.8 3.2 75 DLR platform (S edge) 3.3 3.75 6.9 7.1 75 Overhead Line 3.3 7.5 8.1 8.2 375 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Magnetic fields will be less than the potentially significant level expected to interfere with pace makers (1.5 kV/m and 15µT, respectively) in locations of public access. Electric field strengths may be sufficiently high at the Crossrail platform edge to interfere with pace makers. However, these calculations are conservative and do not take account of the shielding effect of the human body and trains arriving at the station. Given that the electric field strengths calculated are comparable with field strengths on existing railway platforms, this potential impact is not considered significant.

Electric and magnetic fields may be of sufficient strength to affect pace makers if people are working directly beneath the catenaries. All personnel working on rail tracks are required to have a Personal Track Safety Certificate. This includes passing a medical examination to determine whether the worker exhibits any conditions likely to cause collapse on or near a line. General advice is given regarding a full range of medical conditions, including exposure to EMF, with particular safeguards provided to reflect the medical condition of the worker. Given these safeguards, the potential impact on workers fitted with pace makers is not considered significant.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.11.3 Choice of Section (2)

Section 2 at Custom House is chosen where the Crossrail and DLR tracks converge, and both are within a relatively close distance to a property at 7–14 Chauntler Close. The pylon supporting the HV electricity line is nearby. This section is illustrated in Figure 5-14

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Figure 5-14 – Custom House Map (Section 2)

Transport for London

© CROWN COPYRIGHT. ALL RIGHTS RESERVED' (GLA - 100032379) (2005) The plan view of the chosen section is shown in Figure 5-15 below. The section is close to the pylon supporting the overhead line, and accordingly the conductors will be at a higher elevation, as shown.

The section is beyond the end of the DLR platforms, but still covers a Crossrail platform.

Figure 5-15 – Custom House – Plan, Section 2

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5.11.4 Custom House (Section 2) – Results.

Table 5-7 – Custom House (Section 2) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant 400 A 0 A Level Level Rear of 7/14 Chauntler Clo. 0.04 3.75 0.16 0.21 75 7/14 Chauntler Clo. (fence) 0.19 3.75 0.25 0.26 75 Victoria Dock Road N side 0.13 3.75 0.34 0.28 75 Victoria Dock Road S side 0.33 3.75 2.1 0.41 75 Wall 0.37 3.75 5.7 0.48 75 Crossrail Eastbound 2.1 7.5 9.3 0.61 375 Crossrail platform (N edge) 2.4 3.75 9.0 0.69 75 Crossrail platform (S edge) 2.5 3.75 9.4 1.1 75 Crossrail Westbound 2.2 7.5 8.6 1.2 375 Wall 0.21 3.75 4.5 1.6 75 DLR tracks 1.4 7.5 2.8 2.4 375 Overhead Line 1.6 7.5 4.0 4.1 375 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

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5.12 Window NE9 – Romford Depot

5.12.1 Sections for Modelling

Sections are chosen along the routes of new alignments and sidings where electrified tracks are to be constructed close to domestic premises. Each Section is chosen by inspection of the overall alignment drawings to select the closest approaches.

The depot is expected to have its own 25 kV traction power supply, and catenary currents will be those associated with occasional train movements at low speeds. In common with the approach in other locations where additional Crossrail sidings are being provided, catenary currents in the sidings and arrival/departure tracks are taken as much lower and more intermittent in nature than those on the main lines. Magnetic field calculations are based on the maximum emergency feeding arrangements on the main lines, which are equipped with booster transformers.

5.12.2 Section 1 – Turn-off from GEML tracks.

(i) Choice of Section 1

The turn-off from Great Eastern Main Line (GEML)/Crossrail through lines is to the north of the existing alignment. The arrival/departure tracks are then routed via an underpass to the south of the GEML main lines.

The alignment before entering the underpass is alongside playing fields, but at the point where the turn-off commences, the new alignment passes close to properties in Saville Road. On the south side there are car parking spaces on the far side of Crow lane, and the EMFs in this area are primarily those generated by the GEML and will remain unchanged. The plan view of the selected section is illustrated in Figure 5-16.

Figure 5-16 – Romford Depot Map (Section 1)

Transport for London

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Figure 5-17 – Romford Depot – Plan of Section 1

(ii) Romford Depot – Section 1 Results

Total currents in the GEML/Crossrail main lines is taken as 630 A, base current for the study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

Table 5-8 – Romford Depot (Section 1) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level 106 Saville Rd (rear of 0.1 3.75 0.0 75 building) 106 Saville Rd (fence) 0.5 3.75 0.1 75 Crossrail turnoff (trap) 3.1 7.5 1.2 375 Depot Arrival 3.6 7.5 3.0 375 Depot Departure 3.4 7.5 4.9 375 Crossrail down 3.2 7.5 7.9 375 Crossrail up 2.9 7.5 7.1 375 Main down 2.7 7.5 7.1 375 Main up 2.6 7.5 7.9 375 Fence N side of Crow Lane 0.6 3.75 1.3 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

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Potential interference of electrical equipment by elevated magnetic field strengths is discussed below.

5.12.3 Section 2 – West of Jutsums Lane Bridge.

(i) Choice of Section 2

East from the turn off of the main arrival and departure tracks, Crossrail Depot track alignment moves to the south of the GEML via the underpass. Crossrail main running tracks (on existing GEML route) pass a residential district with closest approach to properties on the south side of Bridport Avenue; on the south side of GEML, the closest approach of the new Crossrail alignment is to industrial premises around Crowlands Yard.

The plan view of the selected section is illustrated in Figure 5-18.

Figure 5-18 – Romford Depot Map (Section 2)

Transport for London

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Figure 5-19 – Romford Depot – Plan of Section 2

(ii) Romford Depot – Section 2 Results

Total currents in the GEML/Crossrail main lines is taken as 630 A, base current for the study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

Table 5-9 – Romford Depot (Section 2) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level 25 Bridport Av (rear of 0.0 3.75 0.0 375 building) 25 Bridport Av (fence) 0.1 3.75 0.1 375 Crossrail down 2.6 7.5 7.7 75 Crossrail up 2.8 7.5 5.9 75 Down Main 2.8 7.5 5.8 75 Up Main 2.7 7.5 7.7 75 Depot-Main connection 2.4 7.5 0.8 75 Depot Arrival 2.7 7.5 0.0 75 Depot Departure 2.7 7.5 0.0 75 Retaining Wall 1.5 7.5 0.0 75 Works 0.1 7.5 0.0 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

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5.12.4 Section 3 – Closest approach to Housing on Depot Approaches

(i) Choice of Section 3

As the Crossrail tracks approach the Depot, the railway is situated in land between residential properties on the north side (south of Sheringham Av.) and the southern side (north end of Beechfield Gdns.). Thereafter, the closest approach on the south side is to car parking facilities and the Transco industrial site.

The plan view of the selected section is illustrated in Figure 5-20.

Figure 5-20 – Romford Depot Map (Section 3)

Transport for London

© CROWN COPYRIGHT. ALL RIGHTS RESERVED' (GLA - 100032379) (2005) The section drawing for evaluating electric and magnetic fields is shown in Figure 5-21. Note the qualification expressed previously on the use of symbols for gantries or masts, and these should not be taken as anything but illustrating the relative positions of tracks, catenaries and existing structures.

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Figure 5-21 – Romford Depot – Plan of Section 3

(ii) Romford Depot – Section 3 Results

Total currents in the GEML/Crossrail main lines is taken as 630 A, base current for the study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

Table 5-10 – Romford Depot (Section 3) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level 139 Sheringham Av (rear of 0.1 3.75 0.0 75 building) 139 Sheringham Av (fence) 0.7 3.75 0.9 75 Crossrail down 2.7 7.5 8.4 375 Crossrail up 2.9 7.5 8.5 375 Siding/loop 2.6 7.5 5.6 375 Down Main 3.0 7.5 8.6 375 Up Main 3.0 7.5 8.4 375 Siding/connection 2.9 7.5 2.4 375 Siding/connection (Wash 3.1 7.5 0.6 375 Plant) Siding/connection 3.0 7.5 0.2 375 Stabling Arrival 3.0 7.5 0.1 375 Stabling Departure 2.9 7.5 0.0 375 Depot Arrival 2.9 7.5 0.0 375 Depot Departure 2.8 7.5 0.0 375 Retaining Wall 1.1 7.5 0.0 375 Retaining Wall 0.2 7.5 0.0 375 47 Beechfield Gdns 0.1 3.75 0.0 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

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The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

5.12.5 Section 4 – Stabling Sidings and Oldchurch Hospital

(i) Choice of Section 4

Stabling for Crossrail trains is provided to the north and east of the depot, between GEML and Oldchurch Hospital.

Properties on the north side, in Queen Street and Albion Close are slightly closer to the existing GEML than the chosen property at the southern end of Cotleigh Road, but a line from the latter to a wing at the western end of Oldchurch Hospital provides the closest approach to the new Crossrail alignments.

The plan view of the selected section is illustrated in Figure 5-22.

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Figure 5-22 – Romford Depot Map (Section 4)

Transport for London

© CROWN COPYRIGHT. ALL RIGHTS RESERVED' (GLA - 100032379) (2005) The section drawing for evaluating electric and magnetic fields is shown in Figure 5-23. Note the qualification expressed previously on the use of symbols for gantries or masts, and these should not be taken as anything but illustrating the relative positions of tracks, catenaries and existing structures.

Figure 5-23 – Romford Depot – Plan of Section 4

(ii) Romford Depot – Section 4 Results

Total currents in the GEML/Crossrail main lines is taken as 630 A, base current for the study was 800 A, hence a factor of 0.79 has been applied to generate the tabulated magnetic field values.

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Table 5-11 – Romford Depot (Section 4) – EMF Results

Location Max. Electric Field (kV/m) Max. Magnetic Field (µT) Calculated Potentially Calculated Potentially Significant Significant Level Level 51 Cotleigh Rd (rear of 0.1 3.75 0.1 75 building) 51 Cotleigh Rd (fence) 0.2 3.75 0.1 75 Crossrail down 2.6 7.5 8.3 375 Crossrail up 2.7 7.5 8.4 375 Down Main 2.8 7.5 8.2 375 Up Main 3.1 7.5 8.0 375 Siding No.1 2.9 7.5 4.9 375 Siding No.2 3.4 7.5 0.9 375 Siding No.3 3.5 7.5 0.3 375 Siding No.4 3.6 7.5 0.2 375 Siding No.5 3.5 7.5 0.1 375 Siding No.6 3.6 7.5 0.1 375 Siding No.7 3.6 7.5 0.0 375 Siding No.8 3.6 7.5 0.0 375 Siding No.9 3.5 7.5 0.0 375 Siding No.10 3.4 7.5 0.0 375 Siding No.11 2.9 7.5 0.0 375 Retaining Wall 2.7 7.5 0.0 375 Retaining Wall 0.6 7.5 0.0 375 Oldchurch Hosp. 0.1 3.75 0.0 75 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection.

5.13 Window SE2 – SE8 Custom House to Abbey Wood

The methodology for assessing the impacts of EMF along the corridor Custom House to Abbey Wood is similar to that used for the Western electrification (Section 3.1) for the

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surface portion of the railway and Central tunnels (Section 4) for the tunnelled portion of the route (Connaught and Thames tunnels).

Buildings were selected within 20 m of either track as listed in Table 5-12. Note in some cases where buildings cross over tunnels or are located in a street which runs parallel to the surface railway the named property is chosen as the closest. There may be a number of other properties which will be influenced by EMF in the same locality.

Table 5-12 – Properties in Windows SE2-SE8

EB Dist to Dist to Tunnel or Window Building Street Chainage WB m.* EB m. Surface SE2 Custom Ho. Station 17,150 Surface Prince Regent Station SE2 (DLR) 17,500 14.0 17.4 Surface N. Portal, Connaught SE2 Tunnel 17,750 Surface SE2 Hotel Lynx Way 17,850 13 9.5 Connaught SE2 Hotel Festoon Way 17,900 17.5 21 Connaught S. Portal, Connaught SE3 Tunnel 18,330 Surface SE3 Building Oriental Road 18,420 5.8 9.3 Surface SE3 Silvertown Station 18,750 Surface SE4 N. Portal, Thames Tunnel 19,600 Surface SE4 Communications building Factory Road 19,660 16.5 30 Thames SE4 Pumping Station Store Road 19,780 4.5 21 Thames SE4 Residential 171-209 Albert Road 19,840 28 9.5 Thames SE4 North Woolwich Station 20,000 20 0 Thames SE5 Industrial Estate Rope Yard Rails 20,700 0 30 Thames SE5 Royal Brass Foundry Royal Arsenal W 20,880 -15 15 Thames SE5 Verbruggens House 20,950 0 30 Thames SE5 1/13 Samson House Maxey Road 21,450 0 30 Thames SE5 1/13 Maynard House Invermore Place 21,500 30 0 Thames SE5 Residential Clendon Way 21,700 -11.5 11.5 Thames SE6 Plumstead Station 21,950 -8 8 Thames SE6 Pumping Station 22,150 21 9.5 Thames SE6 S. Portal, Thames Tunnel 22,250 Surface SE6 Residential 165 Marmadon Road 23,070 19.8 23.3 Surface SE7 Residential 88 Church Manor Way 23,230 12.8 16.9 Surface SE8 Residential 17 Abbey Terrace 24,350 18.6 23.3 Surface SE8 Abbey Wood Station 24,550 Surface SE8 Residential 40 Halifield Drive 25,450 15.1 18.6 Surface (* Distance to WB track has a negative value when building is between tunnels)

5.13.1 Window SE2-SE8 – Surface Railway

Detailed estimates of the electric and magnetic fields have been made for the properties listed as adjacent to the surface railway and with dimensions to East and West-bound Crossrail tracks shown in Table 5-12.

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The methodology is as used for the Western section, but for simplicity the results are shown in the following Table in abbreviated form, as applicable to the portion of the building nearest to the railway.

Table 5-13 – EMF Results Windows SE2-SE8 (Surface)

Electric Field kV/m Magnetic Field uT Calculated Potentially Calculated Potentially EB Significant Significant Window Building Street Chainage Level Level Prince Regent SE2 Station (DLR) 17500 0.22 7.5 0.57 75 Commercial SE3 Building Oriental Road 18420 0.84 3.75 4.80 37.5 165 Marmadon SE6 Residential Road 23070 0.37 3.75 0.23 37.5 88 Church SE7 Residential Manor Way 23230 0.62 3.75 0.75 37.5 17 Abbey SE8 Residential Terrace 24350 0.50 3.75 0.29 37.5 40 Halifield SE8 Residential Drive 25450 0.52 3.75 0.46 37.5

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection

Electric and magnetic fields will be less than the potentially significant level expected to interfere with pace makers (1.5 kV/m and 15µT, respectively) in locations of public access.

The magnetic fields would not interfere with electrical equipment with the possible exception of the commercial building on Oriental Road (SE3). This building is situated right on the edge of the cut where the tracks rise from the Connaught tunnel to Silvertown Station. However, traction loads are based on maximum planned Crossrail service timetable and feeder currents of 400 A on both EB and WB catenaries (totalling 800 A). These currents will only arise in bursts of maximum duration 1 minute and then only under the most adverse loading conditions, such as an emergency condition in the case of an outage of the normal supply arrangement. In any event, the current use of the building is not expected to include electronic equipment of such sensitivity to be affected by magnetic fields of the strength modelled.

5.13.2 Window SE2-SE8 – Connaught and Thames Tunnels

A number of buildings have been identified over the proposed route of the Thames Tunnel from North Woolwich to Plumstead and the existing Connaught tunnel, which will be equipped with 25 kV traction power supplies.

Information for Table 5-14 has been provided by CLRLL.

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Table 5-14 – Window SE2-SE8, Vertical Profiles

Ground Rail EB Level Level Depth Window Building Street Chainage Tunnel m. m. m. SE2 Hotel Lynx Way 17,850 Connaught 105.8 94.6 11.2 SE2 Hotel Festoon Way 17,900 Connaught 105.7 94.0 11.7 Communications SE4 building Factory Road 19,660 Thames 103.8 90.3 13.5 SE4 Pumping Station Store Road 19,780 Thames 104.1 87.4 16.7 171-209 Albert SE4 Residential Road 19,840 Thames 104.3 85.9 18.4 SE4 North Woolwich Station 20,000 Thames 104.6 82.0 22.7 SE5 Industrial Estate Rope Yard Rails 20,700 Thames 108.9 72.4 36.5 Royal Arsenal SE5 Royal Brass Foundry W 20,880 Thames 109.0 73.3 35.7 SE5 Verbruggens House 20,950 Thames 108.2 73.7 34.5 SE5 1/13 Samson House Maxey Road 21,450 Thames 108.1 74.9 33.2 SE5 1/13 Maynard House Invermore Place 21,500 Thames 107.9 75.4 32.5 SE5 Residential Clendon Way 21,700 Thames 108.4 78.5 29.9 SE6 Plumstead Station 21,950 Thames 105.4 83.9 21.6 SE6 Pumping Station 22,150 Thames 103.5 88.0 15.4

Note: Depth of rail is relative to ground level.

Tunnels provide complete shielding for electric fields, but in the worst case may be transparent to magnetic fields. Moreover, depending on the details of the earthing and return conductor arrangements, significant traction return current may flow in the soil rather than the rails or return conductors. Analysis of this effect is based on the worst-case scenario where booster transformers are not installed, but this decision is under review with a probability that booster transformers may be used in the same manner as the surface railways.

Refer to Section 4.2.2 for a discussion on the effects of different earthing/return conductor strategies and the choice of 5% and 10% return current through the soil.

The results of the assessment of maximum magnetic fields in properties over or adjacent to the Connaught and Thames tunnels are summarised in Table 5-15:

Table 5-15 – EMF Results Windows SE2-SE8 (Tunnels)

EB Field µT Field µT Window Building Street Chainage S (5%) (10%) SE2 Hotel Lynx Way 17850 0.70 1.23 SE2 Hotel Festoon Way 17900 0.39 0.76 Communications SE4 building Factory Road 19660 0.34 0.66 SE4 Pumping Station Store Road 19780 0.49 0.87 SE4 Residential 171-209 Albert Road 19840 0.37 0.68 SE4 North Woolwich Station 20000 0.34 0.63 SE5 Industrial Estate Rope Yard Rails 20700 0.18 0.35 SE5 Royal Brass Foundry Royal Arsenal W 20880 * 0.22 0.42 SE5 Verbruggens House 20950 0.19 0.37 SE5 1/13 Samson House Maxey Road 21450 0.20 0.39

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SE5 1/13 Maynard House Invermore Place 21500 0.20 0.39 SE5 Residential Clendon Way 21700 * 0.28 0.53 SE6 Plumstead Station 21950 * 0.46 0.82 SE6 Pumping Station 22150 0.47 0.85 (code “*” in the column headed “S” flags that the results are based on 100% of total current in the nearest tunnel rather than 50% in each tunnel, since this can give a worst case where a building is situated symmetrically between tunnels). See Section 4.4.

The magnetic field strengths at all properties are calculated to be within the potentially significant level for the protection of public health (75 µT) and for the interference of electrical equipment (3 µT).

These magnetic fields are based on the same 1-minute peak traction currents as used for the surface portion of the route, namely 400 A/catenary. This is less than half the value adopted for the tunnels under central London hence the magnetic fields are proportionately lower.

5.14 Summary of Findings – Eastern Route Sections

Electrical and magnetic fields (EMF) have been assessed for the eastern sections of Crossrail from the tunnel portals at Pudding Mill Lane and Custom House Station to Shenfield Station in the north east and Abbey Wood Station in the south east.

The EMF impacts have been modelled at locations where there will be re-alignments of existing tracks or new Crossrail services, and both electric and magnetic fields have been calculated based on 50 Hz and maximum catenary currents. Other EMF sources, particularly at Custom House Station have been taken into account. The maximum field values at these five locations are summarised in Table 5-16.

The electric and magnetic field strengths are all calculated to be below the potentially significant levels for both public and occupational health protection

The magnetic fields would no interfere with electrical equipment at residential properties.

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Table 5-16 – Maximum EMFs from Crossrail OLE (Eastern Route Sections)

Location Railway/ nearest Max. Electric Field Max. Magnetic Field µT Notes private property kV/m Calculated Potentially Calculated Potentially Significant Significant Level Level

Pudding Mill Railway 2.8 7.5 8.1 375 Lane DLR platforms 0.9 3.75 6.2 75 1 Railway 3.6 7.5 16.7 375 Gidea Park Nearest private 0.6 3.75 1.5 75 2 (sidings) property Railway 3.2 7.5 7.9 375 Shenfield Nearest private 0.4 3.75 0.24 75 3 property Custom Railway 2.4 7.5 9.2 375 4 House DLR platforms 1.9 3.75 7.1 75 Railway 3.6 7.5 8.6 375 Romford Nearest private 0.5 3.75 0.1 75 5 Depot property Custom Ho. to Surface section 0.84 7.5 4.8 375 6 Abbey Wood Tunnel section N/A 7.5 1.23 375 7 Note: Please refer to Table 2-2 for assessment criteria. The potentially significant levels quoted in the table are based on 75% of the appropriate public health protection standards. Notes

1. DLR platforms considered as the nearest private property. Other properties are relatively remote and will have fields of much lower magnitudes 2. Warehouse North Wall (Section 1). 3. Rear boundary of properties in Hunter Avenue. 4. Magnetic field is generated almost in entirety by the overhead power line, not Crossrail. 5. 106 Saville Rd (fence) 6 At nearest building (Oriental Road) 7 At nearest building (Hotel, Lynx Way), with worst-case 10% current through soil.

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6 Summary of Conclusions and Recommendations

6.1 Western Route Section

The Great Western Main Line (GWML) between Paddington and Maidenhead will carry Crossrail services, which requires the track to be electrified beyond Stockley Flyover. The only electric services out of Paddington using 25 kV traction power supplies (OLE) are those of the Heathrow Express.

The principal findings based on study of the representative track sections along the route and a desk-based survey of properties near the GWML are as follows: • EMFs on or adjoining railway land are within the latest limits currently set out by NRPB and ICNIRP for public health. • EMFs on railway property, underneath electrified tracks, will approach, or in the case of voltage fields slightly exceed, the guidelines for people with heart pace makers. This needs to be noted for workers on track sections not presently electrified. • EMFs in public ways adjoining railway land are within the guideline limits for pace maker interference. • A total of 11 buildings have been identified within 10 m of present or future electrified tracks. In eight of these, the magnetic field strength may exceed the “potentially significant” level of 3 µT for interference with sensitive electronic equipment although none of the building uses suggest such equipment is present.

6.2 Central Section

Typical maximum magnetic fields at the ground surface are in the band 1–1.25 µT, over tunnels at typical minimum depth 18 m. The highest value is 2 µT adjacent to tunnel portals.

A sensitivity study with stray earth current 10% yielded an absolute maximum surface field of 3 µT.

The results do not exceed the guideline limits for interference with electronic equipment. The most likely outcome is a factor of safety of at least 2, on these limits.

Refinement of the calculation of stray earth current can only be commenced when detailed engineering studies are carried out to select the optimum design for tunnel OLE.

(i) Susceptible Buildings from the Tunnels Obstruction Study

The conclusions are the same as found by the generic analysis. The guideline level of 4 µT is not exceeded, and the field strengths found on the survey of potentially susceptible properties, with the expected 5% stray current level, were lower by a factor of three or better.

73 Report Volume I of IV (Feb 2005) Assessment of Atmospheric and Air Quality Impacts Mott MacDonald Technical Report CLRL Limited Volume IV of IV

6.3 Eastern Route Section

The principal findings based on a study of the representative track sections along the route and a desk-based survey of properties near the eastern route sections are as follows: • EMFs on railway land, including station platforms (Crossrail, Docklands Light Rail or other railway or LUL services) are within limits currently set out by NRPB and ICNIRP for public health. • Magnetic fields at adjacent private properties meet the requirement set out in the EMC regulations for maximum field strengths in residential or light industrial or commercial premises. • EMFs at Custom House are heavily influenced by the presence of an overhead power line immediately adjacent to the station and running parallel to the tracks. Assumptions have had to be made on the operating voltages and currents of this line, also its physical dimensions, in particular the design ground clearance, which may heavily influence the results.

74 Report Volume I of IV (Feb 2005)