Trains still off-line in Adelaide

Hundreds of commuters stranded for hours on Thursday after major train services failed during Adelaide's morning peak face more delays for the journey home.

Power failed on the Seaford and Tonsley lines in Adelaide's south from 7.30am and the transport department said the outage would continue into the night.

Diesel rail cars will be used to cover from Adelaide to Brighton and buses will take passengers from Brighton to Seaford.

There will also be substitute buses from the city to Seaford.

"Investigations are continuing into the cause of the power outage at the Lonsdale substation," the department said.

"Every effort is being made to restore full services as soon as possible."

Passengers have also been asked to consider alternatives.

During the morning peak hour, passengers were stranded at stations and others forced to walk from disabled trains.

In one case a ladder was used to get passengers down from one train stopped between stations.

Buses were sent to ferry frustrated commuters to work but many were delayed for hours.

"Even my mobile phone has more power than Adelaide Metro's Seaford Line," one woman tweeted.

"I literally go to uni one day a week. This week the trains aren't running. I swear Adelaide Metro are the worst service," another said.