Initial train crash findings released

The Rail Accident Investigation Branch (RAIB) has provided an update on its investigation into the tragic train collision near Talerddig, Powys, which took place on the evening of October 21, 2024.

The accident, involving two passenger trains operated by Transport for Wales on the Cambrian line, resulted in the death of one passenger and serious injuries to four others, with a total of 16 individuals requiring hospital treatment.

The incident occurred at approximately 7:26 p.m. when the Shrewsbury to Aberystwyth service (train 1J25) collided with the Machynlleth to Shrewsbury service (train 1S71), around 900 meters west of the Talerddig passing loop. Despite both trains sustaining significant damage to their leading vehicles, neither derailed.

Preliminary analysis suggests that the westbound train (1J25) had been scheduled to stop at the Talerddig loop to allow the eastbound train (1S71) to pass. However, data from the On-Train Data Recorder (OTDR) on 1J25 indicates that although the driver applied the brakes as the train approached the loop, the train continued moving. The system registered an emergency brake application that persisted until the impact, yet the westbound train entered and then exited the loop, continuing on the single track for about 900 meters before the collision.

Evidence suggests that the speeds at the time of impact were between 24 and 39 km/h for 1J25 and around 10 km/h for 1S71.

Both trains involved were Class 158 diesel multiple units, equipped with wheel slide protection (WSP) and an automatic sanding system, similar to anti-lock brakes in vehicles, designed to help prevent wheel slip by applying sand to the track during braking.

However, RAIB’s inspection of train 1J25 revealed a blockage in the sanding hoses, which likely hindered the effective discharge of sand at the critical time.

The investigation has also noted low wheel/rail adhesion levels on the track approaching Talerddig. The RAIB is exploring whether these conditions, combined with the malfunctioning sanding system, contributed to the train’s inability to stop at the loop.

The investigation by the RAIB will continue in the coming months, with findings expected to inform potential safety recommendations aimed at preventing similar incidents on the Cambrian line and other rail networks across the UK.