Well I updated my TS12 to the latest build today ( don't ask me how I neglected to do this for the last 3 months)...I was running the Blue Comet steam engine with the passenger cars on the very flat Cotton Belt Route, and I had saved a session prior to the update, with my train parked on a single track stretch. When I started the session back up again I immediately hear this hissing sound like a pressure cooker gone whacky. Hmm, hadn't ever heard that before, then I noticed that the blow off valves on top of the boiler were spewing steam out like crazy 
. Steam pressure was 245 PSI. I guess the update must have changed the dynamics of how the engine responds to an over pressure, because I had seen pressures on this engine in that range before but never had the blow off problem. Since I am currently reading a book on steam locomotives and their development, I figured this was a good practical test to see if I learned anything, and could stop this darn hissing noise.
I adjusted the water up towards 70%, and kept going up to 100% with almost no drop in pressure ( there goes that theory) . I had the regulator pretty close to zero, since on the flat run with only 5-6 passenger cars, the loco wants to clip along over the posted speed limit of 55 mph, by about 5 mph, with almost no throttle. Well, I left the cutoff at +75% so it would use as much steam as possible, but still pressure was too high and blow off valves still kept hissing like crazy. ( I think if I had been on a real locomotive cab , I would have been running for the exit door by this time). I made sure the blower was turned off, and then I decided that maybe overfilling the firebox with coal, didn't seem to be lowering the pressure, so I was going do the opposite and let the coal level burn down. By the way the fire was not white hot either but a reddish yellow. When I got down to about 55% coal level in the firebox, the pressure started dropping, with the cutoff still at +75%, and now my pressure started coming down and started to settle around 180PSI. I finished the rest of the run with about 50-55% coal and 90-100% water, 175 PSI, and no more blow offs. Interesting run....
. Steam pressure was 245 PSI. I guess the update must have changed the dynamics of how the engine responds to an over pressure, because I had seen pressures on this engine in that range before but never had the blow off problem. Since I am currently reading a book on steam locomotives and their development, I figured this was a good practical test to see if I learned anything, and could stop this darn hissing noise. I adjusted the water up towards 70%, and kept going up to 100% with almost no drop in pressure ( there goes that theory) . I had the regulator pretty close to zero, since on the flat run with only 5-6 passenger cars, the loco wants to clip along over the posted speed limit of 55 mph, by about 5 mph, with almost no throttle. Well, I left the cutoff at +75% so it would use as much steam as possible, but still pressure was too high and blow off valves still kept hissing like crazy. ( I think if I had been on a real locomotive cab , I would have been running for the exit door by this time). I made sure the blower was turned off, and then I decided that maybe overfilling the firebox with coal, didn't seem to be lowering the pressure, so I was going do the opposite and let the coal level burn down. By the way the fire was not white hot either but a reddish yellow. When I got down to about 55% coal level in the firebox, the pressure started dropping, with the cutoff still at +75%, and now my pressure started coming down and started to settle around 180PSI. I finished the rest of the run with about 50-55% coal and 90-100% water, 175 PSI, and no more blow offs. Interesting run....
