Sydney trains: Seven injured after car smashed through fence onto train track on Princes Highway

Seven people have been hospitalised after a multi-vehicle smash on the Princes Highway in south Sydney ended with a car landing on train tracks.

Emergency services attended the scene at Waterfall after the crash at about 6.10am on Friday after reports of a three-vehicle crash in the southbound lanes. The impact of the crash sent one of the vehicles through a fence and onto railway tracks.

A major traffic operation has closed the southbound lanes of the highway, causing significant delays for commuters.

Six men between the ages of 18 to their mid-30s have been hospitalised. Two men were taken to Liverpool Hospital — one by road and one by helicopter — and another two each to St George Hospital and Wollongong Hospital.

The details of the seventh victim are yet unknown.

There are fears not all of the seven people who NSW Ambulance said were injured in the crash have survived.

A local, Marion, told 7NEWS the stretch of road where the crash occurred was “tricky” because of the speed limit.

“It’s an 80km/h zone but a lot of cars are already doing 100km/h when they come through here,” she said.

“There’s a long way between them, the two (crashed cars) that are on the side of the road and pretty badly damaged.

“I just feel very sad for everyone involved and hope that it just makes everyone drive a lot more carefully and be more aware of what’s going on, on the road.

Police are appealing for any witnesses or anyone who was travelling in the area at the time who has dashcam footage to contact Sutherland Police or Crime Stoppers.

Motorists travelling towards Wollongong are being diverted via Heathcote Road, the M5 Motorway, the Hume Motorway, and Picton Road.

Live Traffic NSW advises light vehicles to “consider travelling through the Royal National Park as an alternative route”.