Four faults were detected in a safety system for a train involved in a fatal crash, investigators have said.
Tudor Evans, 66, died and four others were seriously injured when two Transport for Wales (TfW) trains collided near Llanbrynmair in Powys on 21 October.
The trains – the Shrewsbury to Aberystwyth service and the Machynlleth to Shrewsbury service – were travelling in opposite directions on a single line and were meant to pass on an extra section of line, called the Talerddig Loop.
But the brakes on the westbound train heading to Aberystwyth failed to stop it in time and it skidded past the loop, colliding with the eastbound train from Machynlleth.
The Rail Accident Investigation Branch's (RAIB) interim report into the cause of the crash revealed the trains collided at a closing speed of about 30mph (48 km/h).
Previously, the RAIB said an automated system that helped train wheels grip tracks had failed.
It said it had inspected the system fitted to the train heading to Aberystwyth which automatically sprays sand via hoses when a wheel slide is detected during braking in a bid to generate more friction.
