3” Marshall
DIMENSIONS OF 3” SCALE MARSHALL TRACTION ENGINE
Overall Length 51” Flywheel 12 3/4”
Overall Width 21 3/8” Front Wheels 11 1/2”
Overall Height 31 7/8” Hind Wheels 18” dia
Steel Boiler 7” dia x 26 1/4” Long Working Pressure 100– 120 psi
Four Shaft transmission two speeds Cylinder Bore 2 1/8”
Working Governor Water Lifter Stroke 3”
Finished Weight about 4cwt
Overall Width 21 3/8” Front Wheels 11 1/2”
Overall Height 31 7/8” Hind Wheels 18” dia
Steel Boiler 7” dia x 26 1/4” Long Working Pressure 100– 120 psi
Four Shaft transmission two speeds Cylinder Bore 2 1/8”
Working Governor Water Lifter Stroke 3”
Finished Weight about 4cwt
The Marshall is a robust model and is very straight forward to build the drawings are good and easy to follow, there is nothing complicated in the construction.
On it’s first steaming the only thing I had to change was the exhaust blast nozzle, most model engines need some adjustment of the nozzle bore size to get the engine steaming right
A large bore blast nozzle will cause a dull fire and the engine will not make steam, a small bore will make the fire fierce which will have the safety valves lifting in quick time, so you have to find a bore size that allows the engine to make steam with a nice controllable fire, it’s a trial and error job, so I make the blast pipe nozzle removable from the blast pipe, it makes altering the nozzle bore size easy apart from having to remove the chimney, the nozzle can be screwed into the blast pipe, or can be a push fit and held in place with a grub screw
Wheel Building
