An investigation is underway after a train overshot the end of a rail line in Adelaide’s western suburbs.

Public Transport Authority executive director Scott White said the train lost traction about 6:30pm on Tuesday and collided with a buffer stop at Grange Railway Station and derailed next to Military Road.

“Essentially it means the train sort of slips, so it never stopped and the wheels span and the train continued,” he said.

“And then of course we’ve got a buffer stop there which is there for this exact reason, it did its job and stopped that train from going any further,” he said.

Mr White said there were about 20 passengers on board at the time, who were all uninjured and were able to safely disembark. 

Train services between Woodville and Grange had been cancelled, but resumed early this morning.

Mr White said the buffer stops were designed to stop trains travelling at low speeds when entering the end of the line.

“Occasionally they do dislodge the buffer, in this instance they did,” he said.

Mr White said it was unclear why the train derailed and a full investigation would take place.

“As always, any recommendations that come out of that in terms of anything else we can do to prevent something like this occurring in the future will be implemented,” he said.