Gauging Historic Infrastructure for the 21St Century
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Gauging historic Infrastructure for the 21st Century Presented by Bridget Eickhoff RSSB Principal Infrastructure Engineer PWI 23 April 2020 Topics to cover ▪ What is gauging? ▪ Standards for ▪ Recent ▪ Strategy for ▪ Why is it complex gauging developments conventional network ▪ GB historic ▪ GB processes ▪ VS SIC sponsored network ▪ Comparison with R&D ▪ Platforms & other methods ▪ Analysis methods stepping ▪ Platform position ▪ High speed 2 21st Century Gauging 23 April 2020 Confidentiality level What is gauging? ▪Ensuring there is sufficient space (clearance) around a moving train for safe operation: – Trains don’t hit structures – Trains don’t hit other trains on adjacent lines ▪Building the biggest train that will fit through the ‘hole’ ▪Increasing the speed of the train whilst still fitting (including tilting trains) ▪Modifying the size of the infrastructure to permit larger (or different) trains – Including coping with the size of maritime containers ▪ Lengths fairly standard (20ft / 40ft), widths fairly standard (2500 or 2600mm) ▪ Heights have increased 8ft, 8ft6in, 9ft, 9ft6in … – Longer passenger vehicles 20m, 23m, 26m 3 21st Century Gauging 23 April 2020 Confidentiality level The challenge of gauging 4 21st Century Gauging 23 April 2020 Confidentiality level Some history ▪Small trains and large structures give lots of clearance Rainhill Skew Bridge ▪Different railway companies used different structure ‘gauges’ ▪Depended on funding, sponsors … Reproduced courtesy of the Institution of Civil Engineers 21st Century Gauging 23 April 2020 Confidentiality level 5 © Michelle McDonald / A1 Steam Locomotive Trust, 29 May 2015 More history (according to William Heath Robinson!) ▪Standardising track gauge to 4ft 8½in came with Britain’s Gauge Act, 1846 Both images reproduced from Railway Ribaldry (GWR 1935) 6 21st Century Gauging 23 April 2020 Confidentiality level More history ▪Standardising the structure gauge in GB never happened ▪Later railways (eg rest of Europe) generally have a larger structure gauge – Including track spacing (six foot) – Learning from our experience! ▪It is a credit to our predecessors that we are using their network to run sizes and types and speeds of trains that they could never have imagined Reproduced courtesy of the Institution of Civil Engineers © Michelle McDonald / A1 Steam Locomotive Trust, 29 May 2015 7 21st Century Gauging 23 April 2020 Confidentiality level Other consequences of legacy infrastructure – GB track layout ▪Curved platforms – Significant proportion, many in built up areas 22% – 22% less than 1000m radius ▪Conflict between – required clearance at vehicle ends / centre – stepping distance at range of door positions 8 21st Century Gauging 23 April 2020 Confidentiality level Other consequences of legacy infrastructure - platforms ▪Current target position: 915mm height; 730mm offset but: – Most existing platforms not at this position & no requirement to modify them – No budget for major platform works & ‘out of scope’ of other station works – 30% in range for height, 22% in range for offset but only 7% in range for both High Tight Low 22% 30% Wide 9 21st Century Gauging 23 April 2020 Confidentiality level Using our legacy infrastructure for mixed traffic ▪Different types of operation at / past the same platform: – Suburban ▪ Mostly stopping trains ▪ Generally 1/3 and 2/3 door positions – Regional ▪ Some stopping trains ▪ Range of door positions – Inter-city ▪ Speed of pass through – Freight ▪ Range of speeds ▪ Container trains ▪Need to trade off gauge clearance against stepping distance 10 21st Century Gauging 23 April 2020 Confidentiality level Topics to cover ▪ What is gauging? ▪ Standards for ▪ Recent ▪ Strategy for ▪ Why is it complex gauging developments conventional network ▪ GB historic ▪ GB processes ▪ VS SIC sponsored network ▪ Comparison with R&D ▪ Platforms & other methods ▪ Analysis methods stepping ▪ Platform position ▪ High speed 11 21st Century Gauging 23 April 2020 Confidentiality level Gauging processes ▪Larger clearances permit simple processes – Measure the vehicle, measure the structure and allow clearance ▪More complex processes are needed to make best use of restricted space – Analyse vehicle behaviour (usually statistically) ▪Often distinguish between: – Upper sector, more suspension movement (>1100mm ARL for GB system) – Lower sector, less suspension movement (<1100mm ARL for GB system) ▪Standard European process is described in EN15273 but not suitable for UK(GB) application ▪UK(GB) historic network is constrained so have developed more precise processes and data to optimise ▪Modern computer techniques make this more straightforward to apply but still need to be wary of assumptions 12 21st Century Gauging 23 April 2020 Confidentiality level Standards for Gauging ▪European TSIs (Technical Specifications for Interoperability) – INF TSI, Loc&Pas TSI, WAG TSI all reference EN15273 for gauging process ▪UK(GB) has Specific Cases (permissions) to use National Rules: – GMRT2173 Requirements for size of vehicles and position of equipment – GIRT7073 Requirements for the position of Infrastructure and for defining and maintaining clearances – GERT8073 Requirements for the application of standard vehicle gauges – GERT8273 Assessment of compatibility of rolling stock and infrastructure – gauging and stepping distances – and Guidance note GEGN8573 Guidance on gauging and platform stepping distances ▪Recognised methods in GB: – Use of standard vehicle gauges, Absolute gauging, Comparative gauging or Hybrid gauging (a combination of any of the others) – Also see VS SIC Guide to British Gauging practice (T926) though some things have changed since 2013 13 21st Century Gauging 23 April 2020 Confidentiality level EN15273 Overview Note – a reference profile is NOT an infrastructure shape and is NOT a vehicle shape! ‘GB’ is NOT Great Britain! 14 21st Century Gauging 23 April 2020 Confidentiality level UK(GB) use of standard gauges (infrastructure or rolling stock) ▪Includes the ‘rules for the gauge’ – Different for different gauges! ▪May include assumptions about lengths / types of vehicles / suspension movement ▪May allow for suspension movement ▪May allow for some other tolerances ▪For Rolling stock – UK(GB) has several ‘freight’ vehicle gauges (W6a, …) – UK(GB) now has passenger vehicle gauges (see later) ▪For Infrastructure – UK(GB) has Lower Sector Infrastructure Gauge (LSIG) – UK(GB) has no standard gauge for Upper sector – Upper sector ‘gauge’ is defined by what vehicles are approved to run (with what restrictions) 15 21st Century Gauging 23 April 2020 Confidentiality level Other methods for clearing rolling stock in GB ▪Comparative gauging – Stay within the ‘shadow’ of existing rolling stock – In all conditions, at all locations, at all speeds – Needs an appropriate comparator – Be aware of existing limitations / special conditions ▪Absolute gauging – Compare the ‘swept envelope’ of the vehicle with the actual structure gauge at each location – Needs accurate infrastructure measurements – Makes allowance for track movements, measurement accuracy etc – Consider range of speeds (fastest not always worst, eg inside of curve) ▪Hybrid gauging – combination of above methods ▪Special requirements for equipment that needs to contact: – Wheels / rails, pantographs / OHLE, shoegear / 3rd rail 16 21st Century Gauging 23 April 2020 Confidentiality level Vehicle ‘swept envelope’ ▪Suspension designed to isolate passengers from track input to give a more comfortable ride Centre throw ▪Suspension movements from – Track geometry roughness End throw – Track layout (curves, cant) – Speed Track – Cant deficiency on curves ▪Also need to account for overthrow on curves Bogie Centres (centre and end throw) ▪‘Size’ of vehicle depends on the location and speed ▪In calculating clearance also need allowance for track movement, wheel and rail wear, variation of parameters during maintenance cycle … 17 21st Century Gauging 23 April 2020 Confidentiality level Cant Deficiency & Cant Excess ▪Cant allows gravitational force to balance required acceleration for curve ▪Only ‘balanced’ for one speed ▪Higher speed would require more cant – Cant deficiency ▪Lower speed has too much cant – Cant excess ▪Maximum movement to outside of curve at maximum cant deficiency ▪Maximum movement to inside of curve is more complex 18 21st Century Gauging 23 April 2020 Confidentiality level Trade-off between gauge clearance and stepping distance ▪For an infrastructure project (track or platform) the requirement is the platform position (height and offset) – The stepping distance is of interest but is not the requirement – Step position (relative to standard platform) is a requirement for the rolling stock – Managing the resulting stepping distance at each actual platform is a joint responsibility of train operator(s) & station operator – Rolling stock (and the stepping) may change ▪‘Positive’ clearance is a requirement, ‘normal’ clearances are not – Always consider use of less than normal clearances to improve stepping – Always review track fixity: ‘low’ track fixity may not be appropriate in station areas – Consider what vehicles are actually intended to run and do not gauge for those that don’t (and never will) run (eg Eurostar, …) – Be prepared to challenge assumptions! 19 21st Century Gauging 23 April 2020 Confidentiality level Current Requirements – Platform position ▪Infrastructure TSI – Target platform heights are 550mm or 760mm ▪ Measured from the running surface of the rails Platform – Target offset according