Piloting a 42xx on target 37

From the open landscape here at the Severn Tunnel I suspect that this is the Welsh side rather than teh Bristol end , and Newport's 4130 displaying its identifying circular pilot engine number is on what must have been at thankless task for the footplatemen rostered to those duties , running endlesly through the smoke filled depths of the tunnel assisting heavy freights as seen here.
These " Large Prarie " tanks engines had been developed by Mr . Churchward over many years from the earliest series in 1903 through to the enlarged version in 1912 with later examples coming into service from 1929 through to 1949 , and with Mr . Collett also taking the design further during his subsequent years at Swindon.
Heavy and loose coupled feights running through the Severn Tunnel often had two brake vans at the rear to protect the train in the event of a "break away" of part of the formation within the tunnel.