Severn Bridge Junction signal box, at the south end of the station and built by the LNWR, is the largest surviving mechanical signal box in the world, with a frame accommodating 180 levers, and is a listed building. Whilst the line beyond Abbey Foregate signal box to Wolverhampton has been updated to electronic signalling, Shrewsbury itself is set to remain lever operated for the foreseeable future. As a result of Shrewsbury's joint (GWR/LNWR) history, and having been transferred at different times between the Western and London Midland regions of BR and more recently Network Rail - it is now in the Great Western territory again - the signalling is a diverse mixture of lower-quadrant and upper-quadrant semaphore signals, with a few colour lights too. Crewe Junction, on the north end of the station, accommodates around 120 levers and is of the same design as Severn Bridge Junction.