The Rail Accident Investigation Branch (RAIB) is to investigate how, at around 03:40 on 16 May 2021, a mobile elevated work platform (MEWP) ran away while being on-tracked at a road-rail access point (RRAP) near Belle Isle junction, North London.
The MEWP was due to be used within an overnight possession of the track between Belle Isle junction and Canal Tunnel junction. The machine operator onboard the MEWP was unable to stop the vehicle and jumped from it as it was running away.
The MEWP ran away on a descending gradient (posted as 1 in 28) and travelled along the Up Canal Tunnel line towards St Pancras station. It subsequently came to a stop within a tunnel, with the total distance of the run-away being approximately 700 metres.
No one was injured during the incident and no damage was caused to the vehicle or the infrastructure of the railway.
A preliminary examination by RAIB found that a hydraulic valve on the MEWP’s rail-wheel braking system was not correctly set for operational use and that this was likely to have been the cause of the MEWP not being braked when it was on-tracked. RAIB also found that a similar occurrence on a different type of MEWP had been reported via a National Incident Report (NIR) in 2016.
RAIB will no carry out a formal investigation which will consider:
- The sequence of events that led to the incident;
- The configuration of the RRV’s braking system at the time of the accident;
- Recent maintenance activities undertaken on the machine and the arrangements used to confirm the effectiveness of braking systems following maintenance;
- The methods used to ensure that the machine had effective braking performance when in operational service;
- The arrangements for reporting technical issues relating to road-rail vehicles;
- Any relevant underlying factors.
RAIB will publish its findings once they are complete, a process that typically takes around 10 months.