GAWLER train commuters will experience service disruptions “until further notice”, after a mechanical fault was noted in a number of carriages in the state’s rail fleet.

The Department of Planning, Transport and Infrastructure announced on Thursday Gawler rail line services would change to run only every half an hour and carriage numbers would be cut.

For now, there is no timeline on when these rail services will return to normal.

The fault was first identified when a carriage travelling along the Gawler line at around 1am on Wednesday morning came to a stop.

An inspection found a fault in the diesel carriage’s drive train, with a further investigation finding 50 out of 70 trains in the state’s metropolitan diesel network had the same problem.

Transport minister Stephan Knoll said the “reliability and safety” of the Adelaide Metro train network required the cut to services following the fault.

“Further inspections are being undertaken of these 50 units and we have some replacement parts in stock,” he said.

“The work is being done to fix those units to put them back into service while we source the remaining number of parts that we need and also the specialist labour that’s needed to accelerate the inspections and replacement of these parts… so we can get them back into service.”

Mr Knoll added as trains are repaired, more services will be added back to the schedule, although normal weekend running times on the Gawler line are set to continue.

“It is fortunate at the moment, due to COVID-19, we are seeing patronage levels on our trains around 70-80 per cent lower than what they would normally be,” he said.

“But still, we understand the frustration our commuters have with having to catch a service within a different time frame.

“As we see more units come on board we will put more services back into the service pattern, especially for that morning and afternoon peak.”

Following the slashing of services, photos began to emerge on social media of packed train carriages where commuters were forced to break COVID-19 social distancing requirements.

Opposition transport spokesperson Tom Koutsantonis said the changed services had led to commuter “confusion”.

“It is completely unacceptable to have passengers cramming onto trains, breaching the 1.5 metre social distancing rule,” he said.

“The government has cut $46 million from public transport – are these mechanical issues linked to cuts to maintenance?

“Where is the plan to ensure passengers don’t have to cram onto trains?”