Llangennech fireball train derailment caused by brake failure, investigators say

21 September 2020, 16:32 | Updated: 21 September 2020, 17:25

The train was badly damaged in the incident
The train was badly damaged in the incident. Picture: PA

By Ewan Somerville

The derailment of a freight train in South Wales that sparked a huge fireball was caused by a brake failure, investigators said. 

Ten wagons, each containing 75 tonnes of diesel, derailed and spilled 330,000 litres of fuel into the Loughor Estuary at Llangennech near Llanelli on 26 August. 

A major incident was declared as the derailment caused huge flames and plumes of smoke, forcing the evacuation of nearby homes in Carmarthenshire in the dead of night. 

The driver managed to escape unharmed.

An early investigation by the Rail Accident Investigation Branch found that the brakes on the train’s third wagon locked, causing some wheels to keep turning and others to dig into the wheel itself. 

Read more: Hundreds evacuated after large diesel train goes up in flames

The fire forced the evacuation of local residents
The fire forced the evacuation of local residents. Picture: PA
The derailment sparked a major emergency response
The derailment sparked a major emergency response. Picture: PA

This “false flange”, a raised lip in the wheel, led to the wagon’s right-hand wheel damaging the track while it travelled at about 30mph. 

When the 25-car train reached a set of points to route the train right 100 metres on, the partly derailed wagon continued straight ahead while the locomotive and leading two cars went right. 

Investigators said in preliminary findings: “The third wagon turned over onto its right-hand side and became detached from the wagon in front of it. 

“This caused the points and the track beyond them to be destroyed, and derailment of another nine wagons followed.”

Ten wagons on the 25-car train derailed
Ten wagons on the 25-car train derailed. Picture: PA

The train brakes were then forced on and the locomotive and leading two cars stopped 180m away from the rest of the train. 

The driver looked back and saw a fire had begun raging, so uncoupled the locomotive and drove 400m further from the wreckage. 

Firefighters battled the blaze for 33 hours and environment officials warned the oil spillage would have “long-term effects” on wildlife in the area.

A preliminary British Transport Police probe ruled out criminal intent.

The Welsh Government's transport minister, Lee Waters, said passengers could face disruption on the Heart of Wales line until Christmas because the damaged line resembled "something out of a disaster movie".

Buses have been replacing services between Swansea and Shrewsbury, adding hours to the journey time.