[Jonatan]

Yes, that makes alot of sense. I took it for granted this would be understood but good you pointed it out. The max flow rate is dependent on revolutions, the min flow rate by the water valve. The question is if anyone is willing to code it as it's a more complex setup than what I described.

Technically a crosshead- or axle-driven pump could feed the boiler while the loco is stationary with its wheels slipping.

[Traindude]

Jonatan, on 27 April 2022 - 07:51 AM, said:

For steam-driven reciprocating pumps the normal injector function works fine as you open a water feed and turn on steam for said pump, but an animation triggerd by the injector on/off toggle to show the steam pump in action would be a welcome addition.

Perhaps the relevant parts could be called ORTSWaterPump_xx.

Not always. In the case of some steam-driven pumps, particularly on latter-day locomotives that used feedwater heaters (yes, that's a topic for another thread but I'm still trying to prove a point) there's only one control, a simple pump operating valve that throttles the speed of the water pump, so there's no separate steam and water valves. Here's an example. I'm assuming the same can be said for old-time steam-driven water pumps as well.

In these cases, the only controls needed would be K and Shift+K, or L and Shift+L, to throttle the pump.