The beam engine only has one in that location. I haven’t fiddled much with it to be honest. The beam engine also has a working governor that seems to make it tick over at a fairly constant rate no matter how much extra steam is applied. It does, however, run at very slow speeds, but the governor keeps it from over-reving. Does that make sense?
It appears the similarities between the two models ends with the boiler as the configurations of the moving parts are quite different.
I love running mine. It ticks along at a very constant rate, almost like a clock.
Here is a link to the review I did of the beam engine.
https://www.officeofsteamforum.com/general-discussion/retrol-beam-steam-engine/Cheers mate !