Hi John. ok, so how much coal do the smaller loco engines burn and under what conditions. I realize this must incorporate the issue of what the locomotive is towing, if it is on flat ground, the engine in good maintenance, etc. Let me put the question this way. If you were adapting a locomotive engine for marine use, with a constant drag on the hull proportionate to vessel speed, what would normally be the limiting factors in operation? I've always assumed boiler pressure was the main issue. Also, what kind of on-going maintenance is required on this kind of engine in operation? Oiling? Steamboat engines on inland water ways usually had a mud box and ash box. They drew ambient water up to keep the boilers filled, requiring some kind of filtering to separate out the junk in the water (silt, etc). I've never heard of a locomotive with a condenser. Another question would be what are the rpm limits of the engine? The Singer organization originally claimed they would be swinging a 6-foot propeller to a maximum of 120 rpm in a direct-drive mode. Does this make any sense or is a gearbox required? I also wonder about the requirement for a flywheel to dampen vibration from the reciprocating action of the piston(s). A steamboat would usually have a doctor engine and boiler to run the pump for the boiler initially and adaptable to drive a bilge pump, etc. Does a locomotive engine require something like this?