Trouble driving Big Boy, runaway steam pressure

[dght64]

I'm building a route, and I was testing it with a Big Boy hauling 60 empty flats (2,000 tons total).

I was heading up a 0.5% grade at 40 kph (the speed limit on this winding mountain road) when I saw my boiler pressure climbing. I've read the manual and I know about adding water and coal to cool it down, so I opened up the injector a couple of notches and put in 5 or 6 shovels of coal. It didn't seem to make much difference, and the pressure was climbing up past 1900 kpa (safety valve opens around 2060) so I opened the injector another 3 notches and put in 10 shovels of coal. Pressure is still rising. I opened the injector ALL THE WAY (water level by this point is around 80% and climbing) and shovelled 25 times. A minute later the safety valve opened.

I had to stop shovelling and injecting when the water and coal levels maxed out, and long story short by the time I got to the top of the hill (about 8 km of 0.5% - 0.7% grades) my steam pressure was over 2400.

I restarted the scenario and tried various combinations of using more or less water or coal, but it still builds up too much pressure and I can't seem to make the Big Boy behave.

Is there something I'm not doing right? Or is there something wrong with the physics?

EDIT: Not sure if it matters, but I'm using TS12 and the most current update patch.

 

[Euphod]

That pesky safety valve! I know that you can control it by using the steps you have described, but I also understand that on some locomotives the basic values in the engine file are off. I don't know if that is the case here, however. I suggest you search the forums for any mention of safety valve, and soon you will find the information you need.

 

[dght64]

Thanks, I'll look around. I already did a search for "steam pressure" but most of the questions had to do with running out, rather than too much.

 

[Pendolino]

I cannot check now, as I don't have Trainz installed on this machine, but perhaps the Big Boy enginespec has not been updated to TS2010/TS12 standards, and this may be the cause of your problem, as TRS2006 enginespecs generate far too much steam.

If pressure is already high, however, don't add coal; open the cut-off up to 75% (this will increase steam and water consumption), open the regulator and add water: all of these actions should lower steam pressure.

 

[jjanmarine3]

Hi,

I have had Big Boy running in cab Mode on the Mojave session with around 4000 tons with no problem ( might be too good becuase it was picking up speed amazingly ) . On startoff the water level was 43% and the boiler pressure 265PSI , everything worked normal , the pressure dropped like it should till I and maintained like it should. It looks like the problem is not on Trainz side then ? Hope the info helps.

Jan

 

[drewhosick]

Yeah I had the same problem. What I found was yeah, shovelling coal helps it temporarily but then overall you've just added so much to the potential of the fire it will eventually just climb up way past limits. Instead don't do any shovelling, let a little water in(75%) or so and let the pressure drop down for a while and then when you get around 50% coal(give or take) you can start shovelling. Now if you're climbing you might need more coal but when I was going down hill it was really hard to manage.

 

[Vern]

Not the Big Boy, but I had the same issue (infinitely climbing steam pressure) on one of the steamers included in Trainz 12 with the Appalachian Coal route. I reported it to N3V and it was supposed to have been fixed in the last patch, but when I tried the run again same thing kept happening.

 

[dght64]

Thanks, everyone. I'll try some experiments with it and see if I can keep it under control.

 

[RPearson]

I cannot check now, as I don't have Trainz installed on this machine, but perhaps the Big Boy enginespec has not been updated to TS2010/TS12 standards, and this may be the cause of your problem, as TRS2006 enginespecs generate far too much steam.
...

No it was updated and uses a new steam container in the espec. Current trainz-build is 2.8.

Not the Big Boy, but I had the same issue (infinitely climbing steam pressure) on one of the steamers included in Trainz 12 with the Appalachian Coal route. I reported it to N3V and it was supposed to have been fixed in the last patch, but when I tried the run again same thing kept happening.

Not surprising since the steam container used in the espec for the Y6b is identical to the one used in the espec for the BigBoy. Even though the 2 locos' characteristics are different. I guess they saved some money and said close enough.

Bob Pearson

 

[jjanmarine3]

It has happened to me now too. I was going up Avery Hill with Big Boy 1 and a load, I had added a steam filling station and had Big Boy 2 at the filling station as a helper further up the hill because the load was around 3000 ton . During the trip I thought I would get Big Boy two ready and steamed up nicely to be ready to take over from BB1. When BB1 arrived at the station BB2 had steam pressure of over 460 PSI.Two different same class loco's , one with steam problems . Are locomotives values set generically or individually ?

Jan

 

[RPearson]

It's set by the espec referenced in the loco's config. So it is the same for any loco that references that espec. I've tested a lot of steam loco using the new steam physics and they all use significantly less water than they should and they also tend to produce more power than they should. There's also a significant difference in power output going in reverse vs going forward direction. So from what I see there are some problems with the new steam physics.

There are also problems with individual espec and IMO the safeties in the Y6b and BigBoy especs are undersized. Steam flow rates for both should get increased.

Bob Pearson

 

[philskene]

Try this locomotive

dght --

What you describe seems to be a well known "feature" of TS12.

I did some work a while ago to try to overcome the issue. If you want to try an alternative enginespec that might provide more joy look for my "HarborMaster TS12 SP Cab Forward" session on the Download Station. The text under the thumbnail provides a link for downloading the locomotive. Tell me if you find it an improvement.

Phil
_____

Edit --

If you want to see the actual session, go here:

http://www.youtube.com/watch?v=03OEoD2T3Sg