The mass rapid transit DB Class 420 train was on its way from Mainz to Frankfurt on the S14 route.

As he approached the station, the train driver acknowledged the warning of the distant signal (1000 Hz Indusi), but subsequently forgot about it after carrying out platform duties.

With the stop signal put at a braking distance the safety overlap depends on an assumed maximum speed and weight of the train.

Although operation regulations imposed a maximum speed after a distant signal warning it was not enforced.

This disaster led to the extension and rollout of PZB90 – in the final modernisation program of 1995 the Deutsche Bahn equipped 10,000 trains with it (1000 Hz Indusi enforcing a maximum of 45 km/h) and more than 10,000 additional speed restrictions were installed (500 Hz Indusi enforcing a maximum of 25 km/h).