A specialized geared steam locomotive featuring a boiler offset to one side and a multi-cylinder steam engine mounted vertically on the other. The engine drives a longitudinal shaft connected to the wheels via bevel gears. This design provided maximum traction and flexibility, making it the dominant motive power for historic logging and mining railroads operating on steep grades, sharp curves, and poorly laid temporary tracks.
Heard on the job
They restored the old Shay and you can hear those gears whining all the way up the mountain.