Cms Resources Glasgow-Queen-Street
Image of runaway maintenance vehicle at Glasgow Queen Street

The RAIB is investigating a serious accident caused when a road-rail maintenance vehicle ran away and struck scaffolding in a tunnel near Glasgow Queen Street High Level station on Sunday 21 April 2013.

The maintenance vehicle was a mobile elevating working platform (MEWP) that was equipped with both rubber wheels for road running and steel rail wheels for operation on the railway. It was intended to be used for engineering work on a section of track which was under possession (temporarily closed to normal train services).

The runaway started at the Keppochhill road-rail access point, a location within the possession where boarding laid between, and to either side of, the rails provides a flat surface allowing road-rail vehicles to be manoeuvred onto the track. This access point is on a section of railway which slopes downwards at a gradient of about 1 in 45 towards, and through, Queen Street High Level Tunnel before running onto level track as it enters Queen Street High Level station. Shortly before 03:00 hrs the MEWP was being transferred from its rubber tyred road wheels onto its rail wheels. During this manoeuvre the machine operator was controlling the machine by means of a remote control unit which was connected to the machine by a length of cable. As the rail wheels were lowered onto the track the MEWP started to run down the gradient, through the tunnel and into the station where it stopped about one mile (1.6 km) from the access point (and before reaching the buffers at the end of the platform).

No-one was onboard the MEWP as it ran away. However, while passing through the tunnel, the MEWP struck some scaffolding which was being erected as part of the planned engineering work and a person working on this scaffolding was seriously injured. Other members of staff working on the track were able to move clear of the runaway vehicle because they either heard its approach or were warned by mobile telephone.

A preliminary examination by the RAIB has shown that the runaway occurred because the brakes acting on the rail wheels were inadequate to stop the vehicle on the gradient and the road to rail transfer was not carried out correctly. The examination also showed that the MEWP ran through the tunnel without lights.

Rail wheel brakes on MEWPs of the type involved in the accident were intended to be effective on gradients of up to 1 in 29. Testing carried out to date suggests that the brakes may not always perform to this standard. Consequently additional restrictions have been placed on the use of this type of MEWP.

The RAIB’s investigation will identify:

– the sequence of events that led to the runaway;
– the factors influencing the actions of those involved in the operation of the machine as it was being placed onto the track;
– the actual capability of the rail wheel brakes;
– the design, approval, maintenance and/or testing processes that were applied to this type of MEWP; and
– the reasons for the loss of lighting on the runaway vehicle.

The RAIB’s investigation is independent of any investigations by the safety authority (the Office of Rail Regulation).

The RAIB will publish its findings, including any recommendations to improve safety, at the conclusion of its investigation. This report will be available on the RAIB website.