[Jonatan]

Injectors are tempramental things and will sometimes be difficult to start or fail to pick up, then you have to restart them and try again. It's a realistic aspect of the steam operations that would be worth simulating. We have something similar happening with the sand pipe being blocked, prompting turning off and on the sanders. A randomization parameter in the .eng file could specify if and how often it could happen that either injector needs restarting.

An injector also will not function without water being added, they just blow steam through the overflow. This is simulated in function but not in sound, an audiable cue when the injector is failing to pick up or loses water. I suggest adding an additional injector sound stream that will play when the steam valve is opened but not the water valve and when the injector overflows, then once the valve is opened the normal injector sound would take its place.
Railworks/TS:C have this function in several locomotives since years back as shown here: https://youtu.be/W6Ho3sabpJ0?t=210

Finally, all injectors are individuals and some will not start unless the water valve is open a certain amount. In my personal experience some injectors will start with the valve almost fully open while others start with it nearly closed.
It also varies how wide a "field" of adjustment of the water flow before the injector fails to pick up or overflows; some have a wide field and will run at any setting, others a very narrow field that requires constant attention to keep them working.

This section in the .eng file, which I'm not sure what it does in ORTS let alone what it did in MSTS, could be repurposed to decide at what amount of water valve opening the injector will actually start, and how much before it starts to overflow.

	comment( min steam pressure, min water proportion, max water proportion  )
	InjectorLimits1 ( 50psi 0.6 1 )
	InjectorLimits2 ( 50psi 0 1 )

The AI would have to be configured to work with these functions also, restarting the injector as required or knowing how to adjust the water and steam valves. Although to keep things simple these functions could be ignored when AI fireman is turned on and only apply when it is turned off.