At least one person died after two express trains collided near the centre of Zurich.
Police said around 45 others were injured in the crash which occurred during Friday evening’s rush hour.
Police said a 22-year old woman from the Czech Republic was killed in the crash which happened near Zurich-Oerlikon station.
The exact cause of the collision is not yet known, but Walter Kobelt, who is heading investigations into the crash, said a brake failure was one possible cause.
However, he did not rule out human error. “One of the trains, the 'Cityvogel', did not stop at a red light,” Kobelt said at a press conference on Saturday morning.
Investigators are currently examining whether the brakes of the Cityvogel were working and whether the train underwent an obligatory brake test before its departure from Zurich’s main station.
Railway officials said the two trains, carrying a total of 1,400 people, crashed sideways into each other, causing one car to overturn and derailing several others.
One of the trains was coming from Schaffhausen towards Zurich, and the other was heading towards Constance in Germany.
The crash occurred at the exit to Oerlikon station, which is an important stretch of track linking the city with Switzerland's main airport.
It is the second fatal railway accident in Switzerland this year, following a head-on collision near the mountain resort of Interlaken in August in which one person died.
swissinfo with agencies
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