SYDNEY'S rail system was plunged into chaos for the second day in a row yesterday, with the situation ­becoming so dire that Sydney Trains ironically started telling commuters to try to avoid travelling with them ­altogether.

Thousands of furious commuters were left stranded at Sydney's Central Station in sweltering temperatures last night with eight of the network's 10 train lines no longer running to a timetable and no expected departure times available.

Crowds became so large that passengers were turned away at some platforms, station stairways at Wynyard were at one stage completely locked off and police were called in to supervise increasingly tense travellers.

While Transport for NSW has blamed the delays and cancellations on lightning strikes and drivers chucking sickies, the train workers' union labelled the transport crisis a "cover-up" for failures in the new Sydney timetable introduced in November.

Horror commute stories included reports that journeys from Ashfield to Central which usually take just 15 minutes were taking two hours and passengers were thousands of dollars out of pocket after missing flights as a result of the chaos.

Opposition Leader Luke Foley blasted the delays and cancellations as "shambolic", slamming Transport Minister Andrew Constance for cancelling services on a week in which most Sydneysiders were returning to work from their Christmas holidays.

"Frankly the new timetable isn't worth the paper it's written on," he said.

"Our public transport is shambolic ... the Govern­ment needs to get back to delivering the key services people rely on."

However, Mr Constance last night would not confirm whether the State Government would launch a review into the debacle.

"The Minister has been regularly updated throughout the day and is returning to Sydney tonight for further briefings," a spokeswoman for the minister said.

Rail, Tram and Bus Union secretary Alex Claassens said commuters were being forced to deal with transport chaos "on a daily basis" as a result of the "terribly put together timetable".

"Management is scrambling to come up with daily excuses for the mess, but the reality is it's all to do with a poorly put together timetable.

"Rail workers are ­concerned that the NSW Government's new train timetable is putting the safety of commuters at serious risk.

READ MORE: Dog boards Sydney train for rrruff-hour commute

"The pressure the new timetable is putting on the system has the potential to impact on other areas of the transport network such as cleaning, fleet maintenance, training and facilities."

At Central Station last night commuters were crammed in like sardines on the platform, waiting for up to an hour for trains to arrive ­already packed full of people.

Announcements blamed the delays on "operational ­issues".

Nerina Shroff From Hornsby said she had never seen scenes like those at ­Central Station.

"Usually I would have been home after 45 (minutes) but I am still stuck in the city," she said.

"I have never seen anything like this. They shouldn't have scheduled track work this week."

Jess Floyd left work two hours early to catch a flight to Melbourne but grew increasingly tense as she struggled to get on a train.

"I'm starting to panic," she said.

"I left work two hours early and I'm still here - just trying to get to the airport it shouldn't be that hard."

Sydney Trains and NSW TrainLink last night tweeted recommending commuters "use local bus routes whenever possible" and delay non-essential travel.

Sydney Trains chief executive Howard Collins said the cancellations were due to a driver shortage with between 65 and 75 drivers calling in sick.

He said they were working on recruiting more drivers.

"This is genuine sickness," Mr Collins said. "People have worked very hard over the Christmas ­period."

SYDNEY'S rail system was plunged into chaos for the second day in a row yesterday, with the situation ­becoming so dire that Sydney Trains ironically started telling commuters to try to avoid travelling with them ­altogether.

Thousands of furious commuters were left stranded at Sydney's Central Station in sweltering temperatures last night with eight of the network's 10 train lines no longer running to a timetable and no expected departure times available.

Crowds became so large that passengers were turned away at some platforms, station stairways at Wynyard were at one stage completely locked off and police were called in to supervise increasingly tense travellers.

While Transport for NSW has blamed the delays and cancellations on lightning strikes and drivers chucking sickies, the train workers' union labelled the transport crisis a "cover-up" for failures in the new Sydney timetable introduced in November.

Horror commute stories included reports that journeys from Ashfield to Central which usually take just 15 minutes were taking two hours and passengers were thousands of dollars out of pocket after missing flights as a result of the chaos.

Opposition Leader Luke Foley blasted the delays and cancellations as "shambolic", slamming Transport Minister Andrew Constance for cancelling services on a week in which most Sydneysiders were returning to work from their Christmas holidays.

"Frankly the new timetable isn't worth the paper it's written on," he said.

"Our public transport is shambolic ... the Govern­ment needs to get back to delivering the key services people rely on."

However, Mr Constance last night would not confirm whether the State Government would launch a review into the debacle.

"The Minister has been regularly updated throughout the day and is returning to Sydney tonight for further briefings," a spokeswoman for the minister said.

Rail, Tram and Bus Union secretary Alex Claassens said commuters were being forced to deal with transport chaos "on a daily basis" as a result of the "terribly put together timetable".

"Management is scrambling to come up with daily excuses for the mess, but the reality is it's all to do with a poorly put together timetable.

"Rail workers are ­concerned that the NSW Government's new train timetable is putting the safety of commuters at serious risk.

READ MORE: Dog boards Sydney train for rrruff-hour commute

"The pressure the new timetable is putting on the system has the potential to impact on other areas of the transport network such as cleaning, fleet maintenance, training and facilities."

At Central Station last night commuters were crammed in like sardines on the platform, waiting for up to an hour for trains to arrive ­already packed full of people.

Announcements blamed the delays on "operational ­issues".

Nerina Shroff From Hornsby said she had never seen scenes like those at ­Central Station.

"Usually I would have been home after 45 (minutes) but I am still stuck in the city," she said.

"I have never seen anything like this. They shouldn't have scheduled track work this week."

Jess Floyd left work two hours early to catch a flight to Melbourne but grew increasingly tense as she struggled to get on a train.

"I'm starting to panic," she said.

"I left work two hours early and I'm still here - just trying to get to the airport it shouldn't be that hard."

Sydney Trains and NSW TrainLink last night tweeted recommending commuters "use local bus routes whenever possible" and delay non-essential travel.

Sydney Trains chief executive Howard Collins said the cancellations were due to a driver shortage with between 65 and 75 drivers calling in sick.

He said they were working on recruiting more drivers.

"This is genuine sickness," Mr Collins said. "People have worked very hard over the Christmas ­period."