Chaos On Sydney Trains After Major Peak-Hour Breakdown

Commuters are frustrated tonight as the Sydney train network again goes into meltdown, thanks to a major breakdown in the city in peak hour.

Train passengers have reported packed platforms, delayed trains and carriages full to bursting on Monday afternoon.

It comes after a breakdown at Museum station, an integral hub in the city centre.

"Allow plenty of extra travel time away from the city due to a train requiring mechanical repairs at Museum earlier," Transport NSW advised.

"Buses are supplementing some trains between Campbelltown and Macarthur. Listen to announcements and check indicator boards."

As of time of writing, the T3 and T8 lines -- heading west and south-west from the city -- were the most affected, but the flow-on effects are hitting other passengers.

Some passengers reported trains crawling along the city tracks, with one person claiming it took her an hour to travel just a few stops.

"So many people have now crammed onto this train that the doors are having trouble closing! How is this safe?" one person wrote on Twitter.

Others claimed they were having trouble even getting onto the train to start with, as long lines snaked from the platform down into passenger walkways.