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Description
The "Gearbox" class, as she and her sisters had affectionately become known, were built for the sole purpose of helping heavy drags up "Sandpatch" Grade. Not a single axle was unpowered, a series of camshafts and bevel gears transferred power from the driving axles to the leading and trailing axles. With the full weight of the coal and water placed over the wheels, not a single pound of tractive effort was lost. To relieve the stress on the gears at high speed running the gears and camshafts could be disengaged via a set of control leavers in the cab.

The locomotives were given ample supplies for stationing at the foot of every grade on the SP&S, an enlarged coal bunker allowed for more coal to be carried with the engine (though caused clearance issues with some of the older tunnels, one engine even had her bunker ripped off!) and the 2 water tanks usually allowed for the trip up and down the hill. In the event the locomotive's water supply was not large enough, the locomotive sported a water siphon, a filter and a long hose for gathering water from any nearby creek.

Even the crews comfort was not spared in the design of the locomotive. Because the cab roof would be covered by the coal in the bunker, 2 ventilation ducts stuck out the side to gather cool outside air and spit it into the cab. When the locomotive entered a tunnel, or during the wintertime, the ducts could be sealed.

Though the locomotives had a less than glamorous jobs, they received the SP&S's standard Tank Engine Scheme.

"Gearbox" number 74 poses for her builders photo shortly after construction. She was the 4th locomotive of the class, built in 1926.

Description
The "Gearbox" class, as she and her sisters had affectionately become known, were built for the sole purpose of helping heavy drags up "Sandpatch" Grade. Not a single axle was unpowered, a series of camshafts and bevel gears transferred power from the driving axles to the leading and trailing axles. With the full weight of the coal and water placed over the wheels, not a single pound of tractive effort was lost. To relieve the stress on the gears at high speed running the gears and camshafts could be disengaged via a set of control leavers in the cab.

The locomotives were given ample supplies for stationing at the foot of every grade on the SP&S, an enlarged coal bunker allowed for more coal to be carried with the engine (though caused clearance issues with some of the older tunnels, one engine even had her bunker ripped off!) and the 2 water tanks usually allowed for the trip up and down the hill. In the event the locomotive's water supply was not large enough, the locomotive sported a water siphon, a filter and a long hose for gathering water from any nearby creek.

Even the crews comfort was not spared in the design of the locomotive. Because the cab roof would be covered by the coal in the bunker, 2 ventilation ducts stuck out the side to gather cool outside air and spit it into the cab. When the locomotive entered a tunnel, or during the wintertime, the ducts could be sealed.

Though the locomotives had a less than glamorous jobs, they received the SP&S's standard Tank Engine Scheme.

"Gearbox" number 74 poses for her builders photo shortly after construction. She was the 4th locomotive of the class, built in 1926.