San Francisco ? Several dozen people were injured when two San Francisco light-rail trains collided Saturday afternoon at the West Portal Station, authorities said.

Forty-seven people were taken to hospitals — four with what appeared to be severe injuries — when a San Francisco Municipal Railway L train rear-ended a K train at the boarding platform about 2:30 p.m., officials said.

“This is probably one of the largest multiple-casualty incidents in recent years (in San Francisco),” said Pat Gardner, a deputy chief with the San Francisco Fire Department.

Witnesses said the westbound L train barreled into the K train as it emerged from a tunnel connecting downtown San Francisco to the city’s western neighborhoods.