I’ve been thinking of the reverser as like a form of gearing to extend the top speed of a steam loco but I’m now having second thoughts, thinking that it may actually be more of a torque adjuster. Is there a good explanation anywhere ? I think I know the basic layout - that it’s a piston that controls the injection and exhaust to/from the driving piston. What’s the difference in the way it functions at, say, 75% and 30% ? And I’ve been bought up in an environment where we used the term reverser - I’d never heard it referred to as the cut-off before playing TS. Why the different words ?