A union is threatening more strike action after stopping trains running on the Glasgow Underground.
The strike centres on a disciplinary issue
Staff at stations across the network walked out at lunchtime on Friday and stayed out for about five hours.
The action was called after a Transport and General Workers Union official was disciplined by the operating company.
Strathclyde Passenger Transport (SPT) said no trains ran on the subway during the strike, although some free buses had been laid on for passengers.
Director of operations Douglas Ferguson said alternative bus services were provided free of charge between Shields Road station and St Enoch and Govan and Partick during the action.
Mr Ferguson apologised for any inconvenience the industrial action caused.
SPT said talks aimed at resolving the dispute would continue and both sides were due to meet at the conciliation service Acas on Monday.
However, the union said there was the potential for an escalation of action.
It said there could be further stoppages during the morning and afternoon rush hours unless a deal is reached.