Faults with track sensors have reportedly led to some South Coast trains travelling through level crossings when the barriers are up in the air and the flashing lights are off.
These “ghost trains” have also been known to simply disappear off the screens at the central monitoring base, meaning staff don’t know their exact location.
A source within Sydney Trains told the Mercury that Sydney Trains had been aware of the issue “for years” but didn't see as a “priority” to fix it.
The Mercury is unaware of this issue causing any accidents or injuries.
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The source told the Mercury that the issue happened with the diesel Endeavour trains, used on the South Coast line between Bomaderry and Kiama.
It is understood that Endeavours have travelled through the Kembla Grange level crossing, while the barriers failed to come down.
Boom gates at level crossings are lowered automatically after a track circuit – which are at intervals of between 20 to 500 metres – detects an approaching train.
Once the train passes, the sensors detect it has left the area and the boom gates are raised again.
The risk of colliding with a vehicle at the level crossing has some train drivers scared.
The heart of the issue, according to the source, is that the wheels on the Endeavours are on a 45-degree angle to the track.
That means the wheels don’t maintain a connection with the track and therefore don’t trip the sensors that control the boom gates.
It is not known if this has happened with other level crossings in the Illawarra though it is understood other trains on the line do not have this fault.
Some train drivers are reportedly scared of driving the Endeavours, because of the risk of colliding with a vehicle or pedestrian at the crossing.
The same flaw is why the Endeavour trains have been known to “disappear” off the control centre screens – for as long as 10 seconds.
It is understood Sydney Trains has planned to attach devices to the wheels to get around the problem.
In the meantime, drivers have been instructed to treat all level crossing as faulty and come to a stop before travelling through.
A spokesman for TrainLink NSW confirmed this issue but said it only occurred on "rare occasions" when the train was not carrying passengers.
"Steps have been taken to prevent accidents at level crossings and ensure trains are detected by signal systems," the spokesman said.
"There have been no related accidents."