Definition of "sidelong"

The passenger train was signalled from one of the west end bay platforms along the Down South Line; as it passed through a crossover to the Up South Line the freight train, which had been travelling slowly to the Up South Line, over-ran the signal protecting the crossover and came into sidelong collision with it.

1961 February, “Talking of Trains: Collision at Newcastle”, in Trains Illustrated, page 76