Two freight trains collided near Gifhorn on Thursday morning.
Several wagons were damaged in the accident in Lower Saxony, gas escaped at the scene of the accident, as a fire department spokesman said.
A freight train stopped because of a stop signal, then a freight train driving behind it drove up for reasons that have not yet been clarified.
The driver of the train that ran up was injured and taken to a hospital, the driver of the front train was slightly injured.
As a result of the accident, the Hanover-Berlin ICE connection was also closed.
Due to the collision between the towns of Leiferde and Dalldorf, several wagons jumped off the track and partially overturned.
Explosive propane gas is currently leaking from at least one damaged wagon of the approaching train, said the fire department spokesman in the morning.
It is currently being explored how much gas is involved.
However, there is no danger for the population because the accident site is in the middle of a forest.
Because of the accident, the route was closed to train traffic in both directions.
The important ICE connection between Hanover and Berlin is also affected.
According to the fire brigade, the clean-up work on the route will continue.