Emergency services evacuated homes in Llnagennech, Carmarthenshire, last night after a diesel fuel train from Milford Haven caught alight.
The incident was reported at just before 11.20pm on Wednesday, August 26, when a number of carriages of a diesel train had caught alight.
At around 5.30am this morning police began to allow residents to return to their homes.
However, a cordon around the scene will remain in place and people are still being advised to avoid the area.
Two employees were on board the freight service and have now been accounted for and no injuries have been reported.
An emergency services presence is still at the scene.
Dyfed-Powys Police Superintendent Ross Evans said: “This was a fast-moving situation, which was declared a major incident due to the initial risk of harm to people living in the area.
“The policing response was large scale, with officers across the force retained on duty to ensure we had sufficient resources to carry out the evacuation swiftly, as well as the deployment of a logistics specialist to assist and advise our officers on safely moving people from their homes to the reception points.
“The evacuation no doubt caused a significant amount of disruption for those evacuated in the middle of the night, and I would like to personally thank residents for their response, as well as our frontline officers who swiftly moved hundreds of residents out of their homes.
“My thanks also go to our emergency services colleagues for their response, and partners at the local authority for their assistance in finding and opening Bryn School and Llangennech Community Centre as safe points.
“Officers will continue to be visible in Llangennech, and we will continue to work closely with our colleagues at British Transport Police, Mid and West Wales Fire and Rescue Service, Carmarthenshire Council, and Natural Resources Wales to bring the incident to a conclusion.”
British Transport Police said enquiries are underway into the causes of the major incident.
“The fire continues and there is still a substantial risk within its immediate vicinity, so our advice remains for people to avoid the area," said British Transport Police assistant chief constable Sean O’Callaghan.
"Our officers will be conducting initial enquiries into the incident and are in the process of securing key witness statements and CCTV."
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