ScotRail services out of Glasgow Central have been disrupted due to overrunning engineering work.
The work stopped trains from getting out of ScotRail depots on Wednesday morning, the train operator said.
ScotRail said it was trying to “get hold of” seven replacement buses while it gets trains back where they need to be.
However, the operator noted that it would be “tricky to get hold of buses at this time in the morning” due to coach firms being “busy with school runs”.
In a separate incident, a broken down train at Cardonald station meant that services towards Paisley Gilmour Street were unable to stop at Cardonald, Hillington East or Hillington West in that direction only.
ScotRail said that it had a rescue train on the way to remove the broken down one.