The Swift Locomotive Works Throttle Mechanism is a functioning 1/8th scale replica of the throttle used on the Union Pacific's Big Boy locomotive. Even though this throttle mechanism is based on Union Pacific Big Boy drawings, it is applicable to any locomotive which was fitted with an external throttle. For example, if you are modeling any large main-line locomotive (Mikado, Hudson, Northern, Challenger, Big Boy, etc.) chances are it was fitted with an external throttle mechanism.
The Swift Locomotive Works throttle mechanism has three components (purchased seperately) the Throttle Quadrant, the Bell Crank and the Air Seal