Collision between a locomotive and a passenger train in Grosmont, September 21, 2021

1. Important Safety Messages

This accident demonstrates the importance of train drivers undertaking permissive movements in sections occupied by another train at speeds that:

  • allow them to stop at a distance they can see to be clear ahead

  • take into account any limitations in visibility from the active driving position due to the type of rolling stock and the layout of the location.

2. Summary of the accident

At 10.32 a.m., a Class 20 diesel-electric locomotive entering Platform 2 at Grosmont station on the North Yorkshire Moors Railway (NYMR) collided with the rear of a passenger train at the ‘stop. The engine had just separated from a train on platform three which had arrived from Whitby and was starting to wait behind the train on platform two which was to leave later for Whitby.

The locomotive entered platform two at approximately 10 mph (16 km/h) and was scheduled to stop in the unoccupied section of track behind the Whitby service. However, the locomotive collided with the rear of this train at approximately 5 mph (8 km/h).

Five minor injuries were reported among the 175 passengers on the Whitby service, and all were treated by paramedics at the scene. There was damage to the passenger train cars, which were withdrawn from service for several weeks to allow inspection and repair. There was no damage to the locomotive, track or other infrastructure

The locomotive entering platform 2, just before the collision (courtesy North Yorkshire Moors Railway)

3. Cause of accident

The accident happened because the locomotive was traveling too fast to be able to stop within the available distance when the stationary cars ahead first appeared in the driver’s view.

The Class 20 locomotive, designed in the 1950s, only has a cab at one end. This means that a driver’s visibility on the line ahead is much more restricted when the front end is leading, with the driver having to look through a narrow window beyond the side of the locomotive, similar to a steam engine driver.

The Class 20 locomotive involved in the accident was privately owned and was made available to the NYMR while some of its own locomotives were undergoing maintenance. It was not intended for use that day, but was required at short notice after the planned steam locomotive’s Automatic Warning System (AWS) equipment failed an operational test. AWS equipment is required for NYMR trains running on Network Rail’s Esk Valley line between Grosmont and Whitby, and the Class 20 locomotive had operational AWS equipment to allow it to operate on this section.

Driver's view of the queue from the front and rear driving positions

Driver’s view of the queue from the front and rear driving positions

The conductor had the skills required to operate the steam locomotive intended for use on the first Whitby service that day. Although he had held the relevant skills to drive diesel-electric locomotives, such as the Class 25 and Class 37, for about five years, and had driven them on numerous occasions, he did not hold the skill specific to drive the class 20 used as a replacement. Accordingly, he requested the assistance of a traction inspector to accompany him. The role of the traction inspector was not to teach the driver how to operate the locomotive but to help him become familiar with the locomotive and its operation and to assess his competence. The North Yorkshire Moors Railway explained that they considered the traction inspector to have overall responsibility for the driver’s operation of the locomotive.

Details of the move that led to the collision at Grosmont station

Details of the move that led to the collision at Grosmont station

The driver and traction inspector drove Class 20 on the first train on the Network Rail route to Whitby, along with a fireman and cleaner. At Whitby the locomotive circled the train so that the cab led for the return trip to platform three at Grosmont.

Once at Grosmont, the Class 20 was to be replaced on this train by the originally planned steam locomotive, which would take the train to Pickering and back, on NYMR lines not equipped with AWS. As the Class 20 would be required to make an onward journey from Grosmont to Whitby, the signalman and train crew radioed and agreed that the locomotive would be parked in siding two at Grosmont, from where it could easily be coupled with the latter. a service.

To make this move, the Class 20 locomotive had to move forward over the crossing, behind signal 11, and then back through platform two. However, the move to siding two was blocked by the presence of the train waiting on platform two for the departure to Whitby. The signalman and crew intended the class 20 locomotive to move from behind signal 11 into the open space of platform two, behind the service to Whitby. The locomotive would then wait there until the Whitby train departed, before moving to siding two.

This movement from Signal 11 was a permissive movement, where a train is allowed to enter a signal section occupied by another train on the basis that the driver must stop before reaching the occupying train. The NYMR rulebook and signaling system allows for this movement, and it is typically used when coupling a locomotive to a train that is already on the platform. The rulebook requires a locomotive undertaking the move to stop at least six feet from the stationary train. To avoid a collision during movement, the locomotive must be driven in such a way that the driver can stop it at a distance in front of which he can see that there are no obstacles.

The driver initiated the movement of platform three to a position behind signal 11 with the locomotive cab leading. He then changed control desks and began the movement back to platform two, with the cabin end trailing, once signal 11 cleared. He accelerated the locomotive to around the 10 mph (16 km/h) speed limit for the line. The first part of this movement was on a straight track, with the driver’s view of the line in front of him being limited by the body of the locomotive in front of him. Approaching the platform, the line begins to curve to the right and the body of the locomotive further obscures the driver’s view ahead. A reconstruction by the RAIB of the approach and entrance to the platform showed that the driver could only have seen the back of the last carriage of the train ahead of him when the front of Class 20 was about 16 meters from it.

The traction inspector said he recognized that the locomotive was traveling a little too fast for visibility when it entered the platform. However, before the traction inspector could suggest the driver slow down, the firefighter told the driver he thought he needed to slow down. The driver applied a very gentle locomotive brake as the front of the locomotive entered the platform, 27 meters behind the train ahead. The locomotive did not begin to slow until about 20 meters later, after the driver significantly increased brake application, likely in response to the firefighter’s request. By then, the coaches ahead were within the driver’s view, and he moved the train brake to the emergency position. However, although braking slowed the locomotive to about 5 mph (8 km/h), it collided with the rear of the stationary train.

Following the accident, the train driver said that although he knew the train was on platform two, he believed it was further down the platform and there were more space to stop his locomotive. It is also possible that the limited forward visibility compared to that of class 25 and 37 diesel locomotives, as well as the driver’s unfamiliarity with operating this locomotive, affected his perception of the locomotive’s speed and his decision making.

The RAIB considers it likely that these factors combined to cause the driver to enter the platform at a speed from which he could not stop in time to avoid a collision. Although there were four people in the cab of the locomotive when the accident happened, RAIB found no evidence to suggest it caused driver distraction.

During its preliminary review, the RAIB found that the NYMR was unable to provide documentary evidence that the traction inspector involved in the accident held the relevant driving competence for the Class 20 locomotive. This is of concern as it means the Class 20 has been operated on Network Rail infrastructure without either the driver or the traction inspector being able to demonstrate the relevant competence for this class of locomotive. The Traction Inspector had worked on NYMR since 1997 and volunteered for 23 years prior. He had maintained and driven all diesel locomotives operated by NYMR. The Office of Rail and Road (ORR) issued an improvement notice on 7 October 2021 requiring the railway to be able to demonstrate the competence of its drivers to operate both on its own infrastructure and on Network Rail’s Esk Valley line.

4. Previous similar events

RAIB Report 35/2007 (Collision at Swanage Station) describes the collision between a diesel locomotive and a set of cars which were parked in a platform on a heritage railway. The locomotive was being operated from its rear cab and the resulting lack of visibility contributed to the collision. Recommendations made included avoiding driving locomotives from the rear cab, where there is a choice, and planning movements to avoid the risk of collision.

RAIB report 02/2017 (Collision at Plymouth Station) describes a collision between two passenger trains during permissive movement on a busy platform. A recommendation was made to the rail operating company regarding driver training on permissive travel, and to Network Rail on the management of operational risk during authorized permissive travel. It also highlighted a learning point for drivers about being able to undertake permissive movements at a speed at which they can stop before any obstacle, taking into account any limitations in visibility.

The RAIB report 08/2019 (Collision between road-rail vehicles at Cholmondeston) describes a collision which resulted from a vehicle with poor visibility of the line in front of it, driving at a speed incompatible with this visibility. Learning points from this survey highlighted the importance for drivers to recognize visibility limitations when driving such vehicles

Jose P. Rogers