"Ruston Proctor steam shovel "
If you want to see one of those snort and operate. Take in the Paisley or Blyth Steam Shows. The fellow who owns a concrete business in Teeswater Ontario owns it. Restoration was done by the same shop near Lucknow that did some work on our JD model 80 diesel.
Watching the shovel operate demonstrated they didn't worry much about boiler chemistry or heat effiiciency in those days. Exhaust from the steam motors contained a lot of condensate. Routing that hot water exhaust backto the boiler feed water tank would have conserved water, preheatead the water and reduced boiler scaling.