Formal Investigation Report Into the Collision of A
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Formal Investigation Report into the Service Disruption on the Northern Line - 7th October 2008 Reference Number: 07-2008-09-060 LU incident No: 18011119 Report Status Final: 16th February 2009. CONTENTS 1.0 Executive Summary Page 3 2.0 Terms of Reference Page 4 3.0 Methodology Page 5 4.0 The Incident Page 5 5.0 Immediate actions in response to the incident Page 16 6.0 Background to the incident Page 17 7.0 Discussion Page 21 8.0 Review of previous events Page 25 9.0 Conclusions Page 26 10.0 Immediate, underlying / contributory and root causes Page 28 11.0 Recommendations Page 30 12.0 Observations supporting identified existing actions Page 32 Appendix One: Timeline of incident Page 33 Page 2 of 40 1.0 Executive Summary 1.1 Following the derailment of a 1995 Northern Line Tube Stock train (T161) between Morden station and the depot on 7th October 2008 at 00:28, serious disruption to train services was experienced on the line. 1.2 Other trains were prevented from entering Morden Station and subsequently caused 17 trains to become held in platforms on the southbound road. Two further trains (T033 & T016) had stalled in the tunnel section between South Wimbledon and Signal Y2 approaching Morden Station. All passengers were detrained by 01:17. 1.3 Trains started to enter Morden Depot at 02:25 with the last train entering at 05:00. 1.4 The first train (T42) departed Morden Depot for service on the northbound road at 06:32 and the last northbound train entered service at approximately 09:28. In all, 24 trains were brought into service with 12 trains being cancelled. Service trains were then terminated and turned at Tooting Broadway with subsequent disruption to the morning peak service. 1.5 The incident train was re-railed by 09:58. Delays were then experienced in moving the train into the depot, which was finally completed by 12:21 with full running resumed at 12:41. 1.6 Due to the serious nature of this incident and the resulting consequences a Formal Investigation was commissioned. 1.7 The immediate causes of the incident were: • Delays bringing trains in and out of Morden Depot; • Delays in moving re-railed train. 1.8 Underlying causes include: • Delays in clearing routes to enable entry/egress to depot; • Train T161 de-railed on 19 points; • Train Operator moved in wrong direction back across spring worked toggle points (trailing) without authority; • Failure to report train defects to Service Control; • Lack of recovery plans for trains stalled between station and depot; • Loss of traction shoes causing defective Traction Package on car 3; • Numerous gaps in traction current rails over the points and crossings; • Number 18a points blown over and secured (locked out of correspondence); • Traction current kept on until all trains stabled. 1.9 The Root Cause was Lack of Management Control. 1.10 Recommendations are made to address the identified causes and include: • Review of the role and understanding of Silver Control and associated training; • Creation of recovery plans for stalled and derailed trains at key locations; • Identification of all required boundaries between the operational railway and the depots. Page 3 of 40 2.0 Terms of Reference A Joint Formal investigation being led by Tube Lines is required to investigate the derailment of Train 161 at Morden Depot on the 6th October 2008 and the subsequent management of the incident. Trevor Bellis has been appointed as Formal Investigation Leader. The other members of the Investigation Team to support the Investigation are:- Peter Wickham LU HSQE Trained Investigator Rob McNeill-Wilson LU Line Engineering Manager Syd Ward TLL Safety Performance Manager Darren Hillier TLL Network Response Manager Russell Gell TLL Signals and Control Asset Engineer Andy McGlauchlan Alstom Production Manager Dave Thomas LU Train Operations Manager Mick Fraser LU TU RMT Representative Kevin Chown LU TU ASLEF Representative Tony Alfred TLL H&S Representative The Remit for the Formal Investigation is to: • Investigate events leading up to Train 161 becoming derailed and to identify the root cause of the derailment • Investigate the subsequent management of the incident response, with particular reference to the length of time taken to re-rail and move Train 161 into Morden Depot and to restore through running and whether the optimal measures were put in place to minimise the consequential disruption to the Northern line’s Train Service • Make recommendations to prevent similar incidents in the future and minimise the impacts of any future, similar events • In developing conclusions and recommendations, review previous relevant incidents and investigations, in particular to give consideration to the recommendations contained in and actions arising from the Local Investigation Report into the incident involving a defective train at Morden on 30 July 2008 An interim report setting out the facts of the incident, its consequences and any immediate recommendations is required by 12:00 hours Friday 24th October 2008 Commissioned by: Jeff Ellis - Northern Line General Manager, London Underground. Diarmaid O’Tuathail – Director of Health Safety and Environment, Tube Lines. Page 4 of 40 3.0 Methodology As part of the TLL / LU Investigation the information for this report has been obtained using the following methods. • All relevant staff involved in the incident have been interviewed • All reports relating to the incident have been reviewed • Recordings of all radio communications have been obtained and reviewed by the investigation panel • The train downloads have been reviewed by the investigation panel • All evidence has been reviewed at a series of investigation panel meetings 4.0 The Incident Date of Incident: 07/10/2008 Time of Incident: 00:28 through 12:41 Location of Incident: Northern Line The full time line is shown in Appendix One Train Derailment Note: Car number (e.g. Car One) is taken from the normal direction of travel in service i.e. southbound. 4.1 On the 6th October at 16:10 Train Operator (T/Op) of the incident train T161 booked on to start his rostered duty (714) which was due to finish at 00:40. The T/Op went about his duties as normal with no unusual circumstances to report. At 22:41 he picked up Train T161 at Golders Green, travelled to Edgware then reversed, departing southbound at 23:06 4.2 At 00:08 on the 7th October at Colliers Wood, the train developed a traction pack fault which caused the TMS to go into alarm mode. The TMS message read ‘Traction Supply Lost – Car 3’. The ‘Help Text’ which the T/Op accessed stated ‘Inform C/C. No motors - Car 3. Check train not gapped, if fault persists change over when convenient.’ (This requires the T/Op to report the fault to the Service Controller) The T/Op acknowledged the alarm and cleared the message, before continuing in service. The fault was not reported to the Service Controller (SC) as the train is going into the depot and there appears to be no loss of power. In consequence as part of normal operations the train is routed into platform 5 at Morden in preparation for being taken out of service into the depot. 4.3 When the Train reached Morden platform 5, the T/Op completes his platform duties and returned to the leading cab ready to stable the train. 4.4 Signal Y8 is cleared and the train departs from platform 5 across 16 points then across number 17/18 crossover and number 19 points towards the shunters stop board on 44 road. The train reached a speed of 15.79 kph when the train operator shuts off as the speed limit for this area is 16 kph. The T/Op attempted to re-motor after a few seconds, but the train did not Page 5 of 40 accelerate and continued to slow down until it stops with the cab on the leading car between the location of Signal Y28 (depot outlet signal) and number 7b points (see figure 1 and photograph one). 4.5 The T/Op made repeated attempts to motor and the train moves forward slightly on 4 occasions, but reaches no more than 1kph. During this time he operated the GOB (Gap Override Button) on 5 occasions. 4.6 On noticing that the train has stopped short of the entrance to the depot, the Alstom Cabin Shunter (CS1) contacted the T/Op to establish what the problem was and a second Alstom Cabin Shunter (CS2) joined the train to offer assistance. CS2 made several attempts to restore power to the train moving to car 3 in the process and when this did not work, suggested that the T/Op should roll the train back a little in order to bring the pick up shoes of car 6 (51680) over the traction current rails on 18 crossovers. The T/Op was not content with rolling the train back from the front cab, but decided to change ends and make a wrong direction move in order to get car 6 (51680) back on to traction current. At the same time the SC noticed from the signal diagram in the control room that the train had stopped on the crossover and started to issue instructions to hold trains in platforms in anticipation of a delay. SC was unable to contact the train and contacts CS1 to determine what is happening. 4.7 The T/Op shut down leading cab, car 1 (southbound 51679) and opened up the rear cab, car 6 (northbound 51680) The T/Op allowed the train to roll northbound (wrong direction move) back towards No 18 crossover, reaching a speed of 3.44kph travelling approximately 17 metres (approx 1 car length).