Commuter chaos, major delays on Syd trains

Commuters are facing delays on three major Sydney train lines due to "urgent train repairs" taking place at Circular Quay station.

The T2 Leppington & Inner West Line, the T3 Liverpool & Inner-West Line and T8 Airport & South Line are all experiencing delays outbound from the city on Monday morning.

Delays are slowly mounting across the affected lines, with one service to Parramatta via Strathfield running 45 minutes late according to the NSW Transport website.

One T2 to Leppington via Granville service is running 39 minutes late, and numerous other services across affected lines running between eight and 30 minutes late.

One commuter told 2GB's Ben Fordham that his train had been stuck at Mascot station.

"It's basically station by station, we're waiting every 15 to 20 minutes before we can get moving again," he said.

An alert from Sydney Trains says: "There are delays to services travelling away from the city due to urgent signal repairs at Circular Quay earlier".

"Trains continue to run however there may be larger than normal gaps between services, trains may stop on platforms for longer than usual and train stopping patterns may change," a Sydney Trains spokesman said.

Passengers should also listen to announcements and check information displays for service updates.

More to come.