Stuart Turner - the Victoria with Expansion Valve Drive Gear

[skittlesmonkey]

is there a reason there use an expansion valve instead of something like a little turbine to harness the energy of the moment from high pressure to low, or is it just to make the mechanism simpler?

[swithnell]

Thermodynamics isn't my thing, but the expansion valve here is like the advance and retard on an IC engine, it provides he ability to change the steam cut-off timings. In this engine its fixed, but in some engines it's automatically set by using a dedicated flyball governor to change the timings