Saturday's passenger pile-up on an railway station escalator happened after a group of people stopped at the bottom of the escalator - blocking the exit and preventing other passengers from stepping off.

Witnesses said there were screams of panic when people fell on top of each other on the downward escalator at Esplanade station just before 4 o'clock on Saturday afternoon.

Police, ambulance crews and firefighters rushed to the scene and 13 people were taken to hospital - some with suspected spinal injuries.

PTA spokesperson Claire Krol says CCTV footage from inside the station showed no sign of any technical problems with the escalator.

"Early indications are that a group of people stopped at the bottom of the escalator preventing others from stepping off. This led to several passengers falling over one another," she said.

At the time the station was busy with people going home after a Telethon Mega Bingo event at the Perth Convention and Exhibition Centre.