General Motors GP 38 Scale Diesel Locomotive - UNION PACIFIC #2019 - O Scale. The 2,000-HP GP38 was introduced in 1966 to satisfy railroads' need for an intermediate-horsepower road switcher. Features of our model include; navigates 0-27 curves, length 14", height 4", 4 wheel power trucks with traction tires, powered by dual motors, flywheel coasting action, all metal gears, metal wheels, electronic 6-amp reverse board with directional lock-out, True Blast Plus 16-bit polyphonic sound including prime mover, horn and bell, durable ABS plastic shell, die-cast trucks, truck sides, pilots and fuel tank, die-cast operating couplers, dual headlights, sturdy stamped metal handrails.