The event took place early on Monday 19 October 1987. Several days prior, the
Great Storm of 1987 occurred, causing widespread damage to infrastructure across Britain. On the Sunday afternoon, a driver who had been attending to engineering works in
Llandrindod Wells reported flooding along the line. The responsible traffic manager, after investigation and some deliberation, decided to accompany the first train out on the Monday: the 05:27 from
Swansea to
Shrewsbury. The 05:27, which consisted of a two-car
Class 108 DMU, fell into the
River Towy near
Llandeilo at approximately 07:15. The accident was caused by the Glanrhyd Bridge being partially washed away by the swollen river. The train was moving at only , which was the normal speed limit for this bridge.
Carwyn Davies, a nearby farmer (and amateur rugby player for
Llanelli), was investigating the flooding on his farm shortly after 7am. He was from the bridge in a flooded field when he saw—despite the fact that it was still "quite dark and raining"— that a central section of the railway bridge had collapsed onto a "V" shape. He attempted to return to his house to telephone a warning, but had not reached there when he heard the train approaching and saw the first carriage "take off" from the bridge. Davies later helped rescuers to reach the bridge using his
tractor. The primary cause of the collapse was found to be
scour at the downstream end of one of the bridge piers, causing a hole into which the pier eventually fell. A result of the incident was that the procedures for checking railway bridges were tightened. There were no railway accidents in Wales resulting in a passenger fatality between this accident and the
21 October 2024 collision near Talerddig Despite this, no prosecutions took place. A replacement bridge was subsequently constructed at the site. == Inquest ==