So I haven’t been able to find good sources to answer these questions, but I don’t trust my intuition on them either.
What happens if either of the cab crew run their injectors too high?
What happens if a fireman underfeeds or overfeeds coal?
If a boiler reaches the point of a safety valve going off, does this affect its ability to continue the journey?
The safety valve just lowers steam pressure. It has no effect on the mechanical integrity of the locomotive.
Too much water in the boiler will impede the production of steam. It isn’t that you run the injector ‘too high’ but too long. Same would hold true for the water pump, weather centrifugal or piston-type.
If the water level were to spill into the ‘dry pipe’ you run the risk of forcing ‘uncompressible’ water into the steam chest and when the water gets to the cylinders the force would blow the cylinder head off the front of the cylinder.
Underfeeding would create a thin fire and the risk there is that the ‘fire bed’ would be drawn through the flues and out the stack with gaping holes left on the grates.
Overfeeding will first cause huge amounts of smoke, then eventually choke the fire out by starvation. No air would be allowed to flow through the grates and the fire would quickly die out.
As backshop mentions the safety valves simply vent excess pressure, first one, then two and most engines have three safeties. You’re just wasting coal and water. The safeties would be progressively set, say 201, 203 and 205 PSI on a 200 PSIG boiler.
NYC_Fire_0010 by Edmund, on Flickr
Good Luck, Ed
