Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I must admit it was fun to experiment and it is a good demonstration of economy of steam and that there is still enough energy to turn another engine over. As has been pointed out they need to be coupled together to be a true compound and i will try what Gil suggested as both engines have similar sized pulleys, however due to the low pressure there is very little expansion going on and you would need over 60 PSI to notice any efficiency. I actually got both engines to run on as little as 7 PSI showing on the gauge in that setup.

I was thinking you could maybe modify a Jensen #55 to act as a cross compound by swapping out the engine units and fitting a #65 and #20 cylinder assembly, the main problem you would have is that the stroke difference of those two engines is 3mm so some modification/fabrication would be necessary.