Rail Accident Report Collision between a train and tractor at Hockham Road user worked crossing, near Thetford 10 April 2016 Report 04/2017 March 2017 This investigation was carried out in accordance with: l the Railway Safety Directive 2004/49/EC; l the Railways and Transport Safety Act 2003; and l the Railways (Accident Investigation and Reporting) Regulations 2005. © Crown copyright 2017 You may re-use this document/publication (not including departmental or agency logos) free of charge in any format or medium. You must re-use it accurately and not in a misleading context. The material must be acknowledged as Crown copyright and you must give the title of the source publication. Where we have identified any third party copyright material you will need to obtain permission from the copyright holders concerned. This document/publication is also available at www.raib.gov.uk. Any enquiries about this publication should be sent to: RAIB Email: [email protected] The Wharf Telephone: 01332 253300 Stores Road Fax: 01332 253301 Derby UK Website: www.gov.uk/raib DE21 4BA This report is published by the Rail Accident Investigation Branch, Department for Transport. Preface Preface The purpose of a Rail Accident Investigation Branch (RAIB) investigation is to improve railway safety by preventing future railway accidents or by mitigating their consequences. It is not the purpose of such an investigation to establish blame or liability. Accordingly, it is inappropriate that RAIB reports should be used to assign fault or blame, or determine liability, since neither the investigation nor the reporting process has been undertaken for that purpose. The RAIB’s findings are based on its own evaluation of the evidence that was available at the time of the investigation and are intended to explain what happened, and why, in a fair and unbiased manner. Where the RAIB has described a factor as being linked to cause and the term is unqualified, this means that the RAIB has satisfied itself that the evidence supports both the presence of the factor and its direct relevance to the causation of the accident. However, where the RAIB is less confident about the existence of a factor, or its role in the causation of the accident, the RAIB will qualify its findings by use of the words ‘probable’ or ‘possible’, as appropriate. Where there is more than one potential explanation the RAIB may describe one factor as being ‘more’ or ‘less’ likely than the other. In some cases factors are described as ‘underlying’. Such factors are also relevant to the causation of the accident but are associated with the underlying management arrangements or organisational issues (such as working culture). Where necessary, the words ‘probable’ or ‘possible’ can also be used to qualify ‘underlying factor’. Use of the word ‘probable’ means that, although it is considered highly likely that the factor applied, some small element of uncertainty remains. Use of the word ‘possible’ means that, although there is some evidence that supports this factor, there remains a more significant degree of uncertainty. An ‘observation’ is a safety issue discovered as part of the investigation that is not considered to be causal or underlying to the event being investigated, but does deserve scrutiny because of a perceived potential for safety learning. The above terms are intended to assist readers’ interpretation of the report, and to provide suitable explanations where uncertainty remains. The report should therefore be interpreted as the view of the RAIB, expressed with the sole purpose of improving railway safety. The RAIB’s investigation (including its scope, methods, conclusions and recommendations) is independent of any inquest or fatal accident inquiry, and all other investigations, including those carried out by the safety authority, police or railway industry. Report 04/2017 March 2017 Hockham Road UWC This page is intentionally left blank Report 04/2017 4 March 2017 Hockham Road UWC Collision between a train and tractor at Hockham Road user worked crossing, near Thetford, 10 April 2016 Contents Preface 3 Summary 7 Introduction 8 Key definitions 8 The accident 9 Summary of the accident 9 Context 10 The sequence of events 14 Key facts and analysis 22 Background information 22 Identification of the immediate cause 25 Identification of causal factors 25 Identification of underlying factors 40 Observations 41 Summary of conclusions 44 Immediate cause 44 Causal factors 44 Underlying factors 44 Additional observations 45 Previous RAIB recommendations relevant to this investigation 46 Actions reported as already taken or in progress relevant to this report 48 Actions reported that address factors which otherwise would have resulted in a RAIB recommendation 49 Recommendations 50 Appendices 52 Appendix A - Glossary of abbreviations and acronyms 52 Appendix B - Glossary of terms 53 Appendix C - Investigation details 55 Appendix D - Product development, approval and acceptance process 57 Report 04/2017 5 March 2017 Hockham Road UWC Appendix E - Safety Integrity Levels and software design 58 Appendix F - Management of fatigue 59 Report 04/2017 6 March 2017 Hockham Road UWC Summary Summary At 12:30 hrs on 10 April 2016 a passenger train travelling from Norwich to Cambridge collided with an agricultural tractor and trailer on a level crossing at Hockham Road, near Thetford in Norfolk. The train was travelling at 87 mph (140 km/h) when, on the approach to the crossing, the train driver saw a tractor moving closer to the railway tracks. The train driver sounded the train’s horn and applied the emergency brake, but could not stop before colliding with the tractor. The train did not derail, but its driving cab was damaged, and the driver and four passengers suffered minor injuries. The tractor was destroyed, and its driver was seriously injured. The level crossing at Hockham Road is on a restricted byway, and has gates which are operated by crossing users. About one minute before the collision, the tractor driver had obtained permission to cross from a signaller at the Network Rail signal box at Cambridge. The signaller had given him permission to cross when there was insufficient time before the train would arrive at the crossing. This was because the signaller had lost his awareness of the position of the train because his levels of concentration may have lapsed, and his competence to operate the workstation safely and effectively had not been adequately monitored. A system that had been installed at the level crossing in 2012, intended to display green or red lights to crossing users to warn them whether or not it was safe to cross, was not working at the time of the accident. It had been decommissioned by Network Rail following concerns which the company had about the safety integrity of the system. This had meant that users had to telephone the signaller for permission to cross. The RAIB found that Network Rail had not come to a clear understanding with the manufacturer of the system about how the equipment met the required safety integrity level, and having assessed the risks, had decided to turn off the system while improvements were made. An underlying factor was that the arrangements in Cambridge signal box for managing fatigue among signalling staff were inadequate. The RAIB has made three recommendations to Network Rail. The first concerns Network Rail’s approach to managing user worked level crossings, with the intention of either eliminating the need for a signaller to have to decide whether it is safe for a user to cross the railway or providing better information for signallers when making these decisions. The second relates to the processes that Network Rail uses when introducing new signalling equipment whose operating interface differs significantly from existing equipment, and the third covers the management of the competence of signalling shift managers when they also operate signalling equipment. Report 04/2017 7 March 2017 Hockham Road UWC Introduction Introduction Key definitions 1 Metric units are used in this report, except when it is normal railway practice to give speeds and locations in imperial units. Where appropriate the equivalent metric value is also given. 2 The report contains abbreviations and technical terms (shown in italics the first time they appear in the report). These are explained in appendices A and B. Sources of evidence used in the investigation are listed in appendix C. Report 04/2017 8 March 2017 Hockham Road UWC The accident Summary of the accident The accident 3 At 12:30 hrs on 10 April 2016 passenger train 1K77, the 12:04 hrs Norwich to Cambridge service operated by Abellio Greater Anglia (AGA), struck a tractor and animal feeder trailer at Hockham Road user worked crossing (UWC1) on the up line between Harling Road and Thetford, in Norfolk (figures 1 and 2). 4 The train was travelling at 87 mph (140 km/h) when, on the approach to the crossing, the train driver saw a tractor moving closer to the railway tracks. The train driver sounded the train’s horn and applied the emergency brake, but could not stop before colliding with the tractor. 5 The train did not derail but the driving cab was damaged. The train driver sustained minor injuries to his hand. The tractor and trailer separated and were knocked into the cess, clear of the running lines. The tractor driver was seriously injured. Four of the 135 passengers that were on board the train were treated for minor injuries and shock. Location of accident © Crown Copyright. All rights reserved. Department for Transport 100039241. RAIB 2017 Figure 1: Extract from Ordnance Survey map showing location of accident 1 The crossing is fitted with telephones for users to contact the signaller, and as such is classed as a UWC(T) by Network Rail.