36181 Idler Gearbox, 6 Wheel Gearbox, 3 pcs (G-Scale) $12.49 Default Title - $12.49 Quantity Please fill in the form below if you'd like to be notified when it becomes available. 36181 Idler Gear for, 6 Wheel Gearbox, 3 pieces (G-Scale) For all North American Style Starter Set Locos. (Sold separatel Moguls, Camelbacks and Saddletank Locomotives use 36183.)