Illawarra commuters trying to return home from Sydney have been caught up in peak hour chaos, after train and line damage due to storm damage.
Multiple lines, including the T4 Illawarra line and the South Coast line, are affected.
In Thirroul urgent track equipment repairs were required after Monday's severe weather conditions.
Trains were suspended between Wollongong and Thirroul from about 5pm, and "flow on delays" remained on the line for some time.
Just after 6pm, hundreds of people travelling from Central were caught up at Mortdale station after trains on the line were suspended, with not enough buses to transport people to connecting stations.
Sydney Trains said there was a train damaged as a result of severe weather conditions at Sutherland, and an object on the tracks at Caringbah.
They said bus companies had been contacted "urgently" to assist.
"Please avoid non-essential travel & consider other travel arrangements if possible," the T$ Twitter account posted just before 7pm.
"Very limited buses are running btwn Mortdale, Cronulla and Waterfall - we're trying to source more buses to assist with moving customers to their destinations."
One Wollongong commuter described the situation as "chaos" and said there were inadequate staff and infrequent announcements at Mortdale, where passengers were initially directed to alight the trains.
"Why they directed everyone to Mortdale station when we were at Hurstville, which is an interchange, is absurd," he said.
"Mortdale Station has barely any staff, so announcements were infrequent, vague and once you were waiting for the buses you could hear nothing."
By 7.30, Sydney trains said the damaged train had been moved at Sutherland, with "train services resuming shortly between Hurstville and Waterfall".
However, they warned major delays would continue.