An investigation is underway into "malicious damage" to train signalling equipment in Glasgow.
British Transport Police (BTP) said vandals had targeted two axle counters and wiring near Nitshill station - on the line towards Barrhead.
The damage was discovered by an engineer just before 06:30 on Tuesday and caused a number of trains to be delayed or cancelled.
(BTP) and Network Rail are appealing for information about the incident.
Det Con Lorna White, of BTP, said: "This vandalism caused extensive delays to peak-time commuter travel.
"Anyone who has information regarding the identity of those involved is urged to contact BTP or Network Rail as a matter of urgency."
