Western Maryland Shay

The Shay geared locomotives were named after the inventor, Ephraim Shay, and were developed in the late 1870's to meet the transport requirements of the ever-growing lumber industry.  A more flexible type of engine was needed, one powerful enough to negotiate sharp curves and steep grades in the backwoods lumber sites.  In this design, a two or three cylinder vertical steam engine, similar to that used to drive a steam ship is mounted on the side of the boiler, and the connecting rods coupled to a crankshaft are connected to the drive-shafts by universal and slip joints.  Small pinions attached to the drive-shafts engage with bevel gears on the truck wheels.  In this way all the trucks are powered and more flexibility on sharp curves and rough roadbeds is obtained.  

Specifications

Weight:  6.4 kg

Dimensions:  Length 640 mm x Width 108 mm and Height 148 mm

Wheels:  (3 trucks)  Diameter 38 mm made of stainless steel

Gear Ratio:  2:1

3 Cylinder Engine:

Vertical 3 cylinder engine (cylinders made of phosphor bronze)

Bore 10 mm x Stroke 12 mm

2 piston rings made of Rulon around pistons, 

miniature ball bearings on crank shaft

Valve Gear:  Stephenson type

Valve Travel 4.6 mm, cut-off 75%

Boiler Type:  Center Flue type boiler with 3 fire tubes

Gas (Butane) firing

Capacity:  340 cc of water at 80% full

Fittings:  2 x Safety Valves, Regulator valve, Pressure Gauge, Water gauge, Water check valve, Super Heater

Fuel Tank Capacity:  90 cc of butane gas

Tender Water Tank:  Capacity 280 cc of water + available space for R/C equipment

Hand Operation Feed Water Pump installed (Bore 8 mm x stroke 16 mm)

Axle Driven Feed Water Pump:  Bore 6 mm x stroke 6 mm mounted on the leading truck wheels axle

Lubricator:  Roscoe Displacement

Couplers: Open Jaw Knuckle Coupler