Sixteen people have been taken to hospital after a train hit a rail buffer at Richmond in Sydney’s north-western outskirts, with witnesses describing the scene as “chaotic”./ The Guardian

New South Wales police said on Monday that the train had crashed into a buffer at the end of the train line while “slowing to stop at the station”.

A number of passengers and two Sydney Trains employees, including the driver, were treated at the scene.

Police said 11 people were treated at a nearby oval after the accident, and although five people remained on the train to be treated no one was trapped.

The injuries of those taken to hospital included broken bones, but none were considered life-threatening.

An ambulance spokesman said one 31-year-old woman suffered a fractured clavicle. Another 77-year-old woman also suffered a fractured clavicle and was being treated for spinal injuries as a precaution.

A New South Wales Ambulance spokesman said 17 ambulance crews and three rescue helicopters responded to the accident, which happened just before 10am on Monday.

On social media witnesses described a “horrifying train crash”, with “people injured everywhere”.

One caller to Sydney’s 2GB radio who saw the crash said there was an “almighty bang”.

The caller said the train came in at speed and hit the buffer and rebounded. “There was a huge amount of dust,” he said.

The cause of the accident is still unknown. Sydney Trains boss Howard Collins said the train had “hit the buffers pretty hard”.

“It is very concerning [and our] first concern is for those involved in the incidents,” he said.

Collins said negotiations in the heated pay dispute between the rail union and the government would be delayed until lunchtime as a result of the accident.

The NSW transport minister, Andrew Constance, said investigators from the Office of Transport Safety Investigations, the Office of National Rail Safety Regulator and Safe Work NSW would work to determine the cause of the accident.

“My thoughts are with Sydney Trains passengers and crew who have been injured after a Waratah train struck a safety barrier at Richmond station,” he said.

“Safety is our number one priority and we will now work to determine what caused the incident.

“I anticipate the current industrial negotiations between Sydney Trains and union delegates are likely to resume later today after being temporarily suspended following the incident to ensure passenger and staff safety were prioritised.”