Passengers in the back three carriages of the 5.20pm train from Waverley to Helensburgh Central were bemused after discovering the front half of the service had departed without them.
People on board the abandoned carriages at Uphall were forced to activate the emergency release to open the doors as fears grew regarding other inbound trains to the platform.
Passengers say they were left to their own devices for more than half an hour until British Transport Police and an engineer arrived at the scene.
ScotRail say they responded to Monday’s incident as soon as possible after the bizarre situation was flagged up by train staff and the firm’s control team. All six carriages have been removed from active service while the cause of the bizarre incident is being investigated.
Office worker Murray Horn, 25, was on his daily commute home to Livingston when the drama unfolded which left around 70 people piling on to the Uphall platform.
He said: “We were all initially so confused that we hadn’t moved, with no announcement or staff member explaining the delay. It wasn’t until 15 minutes later that someone noticed the first three carriages had gone and we were all just in disbelief and confused as to how this could have happened.
“We broke the emergency glass to escape the train as we didn’t know if a train behind would know we were there. We were tracking the train on the ScotRail app and the train was at Bathgate so who knows when they realised what had happened? It certainly wasn’t a rapid response. Even taxis were beginning to arrive before the police and engineer arrived.”
Customers on board the front three carriages continued on their journey a further two stops to Bathgate, where the service terminated.
Meanwhile stranded commuters took to social media to express safety concerns. Shauna Rafferty tweeted: “No driver, no staff, had to hit the emergency release to get the doors open. No word from ScotRail, absolute shambles!”
Dan McMeeking said: “Surely this is a serious safety issue. Imagine if it was going at speed.”
Jane Smyth posted: “Oh dear, train from Edinburgh to Helensburgh has abandoned three carriages at Uphall. Don’t worry though we managed to get the doors open. Always have safety in mind ScotRail? You’ve finally managed to shock me!”
Mr Horn added: “I feel ScotRail were not in control of the situation at all. What would have happened if the train had decoupled on a junction or between stations? ScotRail has a lot of safety questions to answer. In reality this situation could have been a lot worse.”
The incident caused further cancellations with ScotRail arranging replacement bus services and for ticket acceptance on local bus routes.
A ScotRail spokesperson said: “We are sorry to customers who were affected by this incident. We are working hard to find out the cause and the train has been removed from service.”
A Transport Scotland spokeswoman said: “Safety is a key priority and, as with any incident of this nature, it will be fully investigated by ScotRail and the relevant rail authorities. Until the outcome of this is known, we are unable to comment further.”