An automated system that helps train wheels grip tracks failed on one of the trains involved in a fatal crash in Powys.

The Rail Accident Investigation Branch (RAIB) said the westbound train involved in the head-on collision in Talerddig, near Llanbrynmair, in Powys on October 21, was fitted with a system which discharges sand automatically via hoses when it detects that the wheels are sliding during braking, intended to increase friction between the wheels and the tracks.

The RAIB said an inspection of the train after the accident showed that the sanding hoses on the leading vehicle of the train were “blocked and apparently unable to discharge sand”.

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The preliminary examination of the Rail Accident Investigation Branch (RAIB) into the train crash at has reportedly found that the driver applied service braking to slow the train only for wheel slide to be “constant” during the emergency breaking progress.

The crash proved to be fatal with one person dying as a result, while a further 11 people were injured and taken to nearby hospitals after the crash on on Network Rail’s Cambrian line.

Describing their findings after the crash, RAIB said: “Over the next few days, RAIB worked in conjunction with the British Transport Police, the Office of Rail and Road and the railway companies involved to secure the necessary evidence to support our independent safety investigation.

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“RAIB’s preliminary examination has found that westbound train 1J25 had been due to stop in the loop at Talerddig to allow eastbound train 1S71 to pass. Initial analysis of data from the on-train data recorder (OTDR) fitted to train 1J25 shows that the driver applied service braking to slow the train as it neared the loop at Talerddig.

“Around 40 seconds after the first service brake application, the OTDR records an emergency brake demand being made. This emergency brake demand remained in place until the collision. OTDR data shows that wheel slide started during service braking and was constant during emergency braking.

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“An inspection of the automatic sanding system fitted to train 1J25 after the accident showed that the sanding hoses on the leading vehicle of this train (which would have been active at the time of the accident) were blocked and apparently unable to discharge sand.”

“There is conflicting evidence relating to the speed of the trains at the point of collision. Initial analysis indicates that train 1J25 was travelling at between 24 km/h (15 mph) and 39 km/h (24 mph), while train 1S71 was travelling at around 10 km/h (6 mph) in the opposite direction.

“RAIB is continuing to analyse evidence relating to the collision speed, which remains an area of ongoing investigation.”