I notice that the engine in question is shown as having 11 x 15" cylinders and 34" drivers, a 35" diameter boiler with 78 flues, a total engine weight of 29,900 lbs., and an overall length of 31' 6", whereas Wallace lists Mason c/n 461 as having been built with 10 x 15" cylinders and 33" drivers, a 36" diameter boiler with 81 flues, a total engine weight of 24,000 lbs., and an overall length of 29' 6". Are we sure this is a the same engine? If it is the same then it has to have been massively rebuilt.
-Philip Marshall