' Royal Corps ' locomotive named by Cmdr at Euston . Saluted by a guard of honour of the London Corps Signals , Brigadier Hubert Clementi-Smith, Colonel Commandant of the Royal Corps of Signals , named one of the London Midland and Scottish Railway regimental class locomotives ' Royal Signals '' at Euston Station , London . Photo shows , a general view as Brig H Clementi Smith unveiled the plaque on the new locomotive at Euston . 10 April 1937