The GWR autocoach (or auto-trailer) is a type of coach that was used by the Great Western Railway for push-pull trains powered by a steam locomotive.

When one or more autocoaches are connected to a suitably equipped steam locomotive, the combination is known as an autotrain, or, historically, a railmotor train.

The driver can operate the regulator, brakes and whistle from the far (cab) end of the autocoach; the fireman remains on the locomotive and (in addition to firing) also controls the valve gear settings.

[2] Many GWR suburban services around Plymouth were formed of fixed autotrain formations of four autocoaches, two each side of the locomotive with cabs leading in each direction.

[3][4] Several Great Western locomotive classes included examples equipped to work in autotrains at different times.