 Originally the resident engineers were responsible for the locomotive stock and the first four holders of this post were all primarily civil engineers . In 1863 the new general manager , Morris , commissioned an outside report on the NSR locomotive fleet which recommended the rebuilding of 50 engines . By the time this report was produced a new engineer , Johnson , had been appointed . He undertook the improvements but the results were unsatisfactory and Johnson left in 1870 after only five years in post . The only significant event of Johnson 's tenure was the building of the first engines at Stoke works when three 0 @-@ 6 @-@ 0T engines were built in 1868 . Johnson 's successor , Dodds , fared no better as his patented wedge motion , a type of valve gear , was unsuccessful . Dodds was dismissed in 1875 and a new post of locomotive superintendent created with a locomotive engineer , Angus , in charge . Although only in post for two years Angus replaced all the wedge motions with Stephenson valve gear . 
