A more pre-emptive approach to rail security would stop incidents like the Otford station graffiti attack, shadow transport minister Penny Sharpe said.
Ms Sharpe and Labor candidate for Heathcote Maryanne Stuart visited Otford station on Friday, the site of a brazen graffiti attack in late May.
Officers from the Police Transport Command arrested three men over the attacks this week.
Ms Sharpe praised the investigation by transport bosses but suggested the government's cutting of Transit Officers has reduced security on late-night trains.
"In the past the Transit Officers were on the trains a lot more," Ms Sharpe said.
"The Police Transport Command are doing a good job but they're understaffed and they're spending a lot of time driving around dealing with incidents after they've happened.
"The transport command used to do late-night guarding services and were on the train on a regular basis and people saw them - they had a huge deterrent effect.
"What people are telling me is that they just don't see people on the trains any more providing any security."
Ms Sharpe said the attack at Otford was evidence there wasn't any deterrent effect on the train.
"People think they can stop a train and graffiti it in a well-planned attack," she said.
"That tells you they thought there was very little chance of there being anyone on the train who could stop them."
Heathcote candidate Ms Stuart said the trains - in particular the revised timetable - was a huge issue for residents in the northern suburbs.
Ms Stuart claimed the timetable had been introduced without discussing it with the public.
"It would have been advantageous if people in the community had been consulted before the implementation," Ms Stuart said.
"Setting up a timetable is a major project and there would have been ample time for community consultation to take place then. None of that ever happened, the timetable was rolled out."
A Transport for NSW spokesman refuted Ms Sharpe's claims about staffing issues with the PTC.
"The command has more than 400 officers on the ground and will see a total of 610 police officers patrolling public transport by the end of 2014, in addition to the 150 Transport Officers in the field who tackle fare evasion," the spokesman said.
"The PTC has greater powers and capability than Transit Officers, enabling them to address issues on the network faster and more effectively."
In regards to the revised timetable, the spokesman said that there was a range of consultation options ahead of its preparation.
"Consultation included regional forums, briefings, as well as opportunities to comment and make submissions during the development of the master plan," he said.
"Information was made available on our websites, by email and via telephone information lines. This feedback was provided to timetable developers to include when building the new timetable."