Cruel Train (1995)

In wartime England, a railway official learns that the chairman of the line had sexually abused his wife as a child, then given him the job so he could continue having sexual access to her. The husband and wife kill him together, but are seen by a train driver, who also has problems of his own. The wife tries to divert suspicion by implicating another driver and befriending the witness, but it doesn't go that smoothly.