A TRS19 and above steam engine spec for the final batch (4160-4179) of GWR 5100 class 'Large Prairies'built with a higher degree of superheat. Boiler pressure: 200psi. Tractive effort: 24300lbs. This spec uses real world data and will perform most accurately if used in conjunction with Stovepipe's e-specs for British rolling stock.Please see included readme.txt for further information.