OK, the discussion on boosters prompts a new question.Booster 101 - how does a booster work. Does the "engine" use a piston and cylinder like a small donkey engine?Thanks.Wesley

Generally boosters are a 2 cylinder horizontal steam engine geared directly to two wheels on the rear truck. There were also boosters applied to the first truck on the tender. There is an overspeed arrangement in the gear case to keep from running the booster engine too fast. I don't know the exact speed but boosters were run under 20 MPH. The booster throttle device was part of the power reverse quadrant. When the power reverse was all the way in the corner the booster could be activated but as you hooked up the engine then it would not be possible to start the booster.