Baldwin Boiler Calculations
The Greensands Railway Museum Trust are currently rebuilding 2'-0" gauge Baldwin 4-6-0T No.778 to working order. A new boiler is being built by Bennett Boilers and Ian Gaylor assessed the steam generating capacity of the new design compared to the original as the number of boiler tubes and their diameter had to be changed in the new boiler to comply with current design standards and available tube stock. Calculations were made of the steam consumption of the locomotive at maximum power output under operating conditions and the small loss of thermal efficiency due to the revised tube bundle in the new boiler design. In addition the maximum combustion rate and smokebox vacuum required to achieve the required steaming rate were ascertained. A preliminary assessment confirmed that a conventional single blast nozzle and chimney could generate sufficient smokebox vacuum to burn the required quantity of coal and a design for a new exhaust system preserving the external appearance of the locomotive will be prepared in due course.