About half of all NSW train services were cancelled on Wednesday as the Rail Tram and Bus Union reinstated work bans while mulling over a new pay offer from the state government.
The cancellation rate hit more than 80 per cent during the afternoon travel peak.
Sydney Trains urged passengers to avoid all non-essential travel on Thursday morning as services continued to be cancelled due to the industrial action and severe overnight storms that tore down power lines.
More than 100 train services were cancelled on Thursday morning, while severe disruptions were expected on multiple lines throughout the day.
Transport for NSW rail operations director Jas Tumber said work on the south coast rail line had been completed, so disruptions there would become less likely.
"It was a very challenging day for our frontline teams, which was capped off with the wild storms which knocked out lots of power for the rail network," she told Sydney Radio 2GB on Thursday morning.
"The ability to operate and maintain the railway in its entirety becomes a very challenging proposition."
NSW train drivers appear unlikely to accept a marginally increased pay offer of 15 per cent over four years, but their union has until the end of the day to provide an initial response to the government.
The two sides have been at loggerheads since September, with workers calling for four annual wage increases of eight per cent.
On Wednesday, less than five per cent of services ran on time, with some trains standing still at platforms for more than 30 minutes as more than 300 work bans brought the system to a halt.
The government previously refused to budge from its initial pay offer of 11 per cent over three years - including a federally mandated superannuation increase.
But officials have since said a merger between NSW's two rail bodies and "productivity gains" - which the union tipped to include 100 job cuts - allowed for the slight bump.
Sydney Trains chief executive Matt Longland said he respected the rights of workers to take action but those not completing full tasks would be docked pay.
Wth AAP.
