TRANSLINK is investigating after a double-decker Ulsterbus tried to drive under a low railway bridge in Co Down and got stuck.
The bus, which was being used as a rail substitution service, hit the bridge near Helen's Bay at about 9pm on Thursday night.
Double-decker buses are not normally used in Helen's Bay because bridges in the village are too low.
Translink later removed the bus.
It is understood the company's staff had to let down the bus's tyres before it could be freed from under the bridge.
A spokeswoman said: "We can confirm that an incident occurred last night [Thursday] at approximately 9pm in which a double-decker Ulster-bus struck a railway bridge at Helen's Bay, North Down.
"The bus was removed from the scene and parked locally overnight.
"This morning, the bus travelled back from Helen's Bay to Belfast."