Changing Safety Valve Volume Level

[wva-usa]

I scrapped that loco the first time I tried running the N and W Appalachian Coal run. Didn't have enough power to get out of it's own way. Just replaced it with my USRA 2-8-8-2 TS12 with the modified engine spec, and it runs great on that route with no safety valve screeching . Now if I can just fix the bugs in the route, it would be nice.

There's something amiss with the Y6b. On the Appalachian Coal route, I can pull 60 55-ton (loaded) hopper cars out of Princeton "yard" (where the yard should be if it existed in the route) with the Big Boy and make it up the .5 percent grade that starts just outside the yard limits and continues to a point near the 1st tunnel.

With the Y6b I can only manage five 55-ton (loaded) hopper cars. After an extremely slow start, if I can manage to get it up to about 18 MPH, the Y6b will suddenly take off like a rocket, accelerating to 45 MPH within a few hundred feet. It's like someone lit its afterburners...

Just replaced it with my USRA 2-8-8-2 TS12 with the modified engine spec, and it runs great on that route with no safety valve screeching .

OK, I'll edit this post to add the following, since I've just finished trying out the unmodified USRA 2-8-8-2 TS12 as it comes off the DLS:

I can manage to haul 45 55-ton (loaded) hopper cars out of Princeton yard with this enginespec. Despite its enormass mass. in Trainz the Mallet has horrible adhension. Anything greater than 45 cars and nothing I tried will keep it moving >2-5 MPH -- too much wheel slip. With sanders on, I can get 45 cars moving and keep them moving if I start out at 15% cutoff and keep in the 15-30% cutoff range and use no more than half-throttle until it finally gets up to about 20 MPH. Then, I can the Mallet up the grade to the point where the route levels out and begins its decent downhill on the ~1.5 percent grade. On the largely downhill run to Princeton Junction the engine popped off three or four times. If I fill up coal to 199% there is some little bit of cooling effect on the fire but not very much. Running the water level down or running it up seemed to have little effect on the boiler temperature. The only way I could avoid it popping off is to set a slight drifting throttle and run out as much steam possible on the few sections where the grade does levels out a bit. Keeping the train in the 25 MPH speed range the real trains were run down this grade during the steam era required putting the train in emergency several times.

Comparing this to the real world: The Virginian Railway was hauling 90-car trains on this exact route using Mikados and USRA 2-8-8-2 Mallets. Ben Neal's Mallet using the USRA 2-8-8-2 TS12 enginespec can't seem to match the real world performance -- it can do about 50% of it.

 

[Robert2d6]

There's something amiss with the Y6b. On the Appalachian Coal route, I can pull 60 55-ton (loaded) hopper cars out of Princeton "yard" (where the yard should be if it existed in the route) with the Big Boy and make it up the .5 percent grade that starts just outside the yard limits and continues to a point near the 1st tunnel.

With the Y6b I can only manage five 55-ton (loaded) hopper cars. After an extremely slow start, if I can manage to get it up to about 18 MPH, the Y6b will suddenly take off like a rocket, accelerating to 45 MPH within a few hundred feet. It's like someone lit its afterburners...



OK, I'll edit this post to add the following, since I've just finished trying out the unmodified USRA 2-8-8-2 TS12 as it comes off the DLS:

I can manage to haul 45 55-ton (loaded) hopper cars out of Princeton yard with this enginespec. Despite its enormass mass. in Trainz the Mallet has horrible adhension. Anything greater than 45 cars and nothing I tried will keep it moving >2-5 MPH -- too much wheel slip. With sanders on, I can get 45 cars moving and keep them moving if I start out at 15% cutoff and keep in the 15-30% cutoff range and use no more than half-throttle until it finally gets up to about 20 MPH. Then, I can the Mallet up the grade to the point where the route levels out and begins its decent downhill on the ~1.5 percent grade. On the largely downhill run to Princeton Junction the engine popped off three or four times. If I fill up coal to 199% there is some little bit of cooling effect on the fire but not very much. Running the water level down or running it up seemed to have little effect on the boiler temperature. The only way I could avoid it popping off is to set a slight drifting throttle and run out as much steam possible on the few sections where the grade does levels out a bit. Keeping the train in the 25 MPH speed range the real trains were run down this grade during the steam era required putting the train in emergency several times.

Comparing this to the real world: The Virginian Railway was hauling 90-car trains on this exact route using Mikados and USRA 2-8-8-2 Mallets. Ben Neal's Mallet using the USRA 2-8-8-2 TS12 enginespec can't seem to match the real world performance -- it can do about 50% of it.

Well I tried the Y6b this morning, because I had forgotten what was so bad about it when I first tried it months ago. I placed the locomotive and tender only, on the track, and started off and it took forever to get going pulling nothing but the tender. I also noticed that the front set of drive wheels didn't turn as the rear ones did, which I thought was bizarre. Then as you stated, once it finally got going which was a long time, it took off like the space shuttle. Crazy locomotive, and not one I would even bother to mess with again. Makes a good static display.

 

[wva-usa]

Well I tried the Y6b this morning... I also noticed that the front set of drive wheels didn't turn as the rear ones did, which I thought was bizarre.

The USRA 2-8-8-2 is setup the same way. The rear drivers are the only ones that are "powered". You won't notice only one set of drivers spinning unless you're starting out with around 40 or more (loaded) cars. If both sets of drivers were setup as "powered" then the number of chuffs per driver revolution wouldn't be correct.

I played around with making an e-spec that uses real world values for the USRA 2-8-8-2 today, and using it with the 2-8-8-2 I was able to pull 90 loaded 55-ton hoppers (and caboose) out of Princeton and up the .5% grade, which is the same number of cars that the real Virginian USRA 2-8-8-2 locos used to do on the same exact route.

So it looking like Trainz is capable of coming real close to matching the real world performance of steam locos. The old rule of thumb used by many U.S. railroads to roughly figure how many cars a given locomotive could pull was one 50 ton car for every 1,000 lbs. of tractive effort. So in other words, a USRA light 2-8-2 with a tractive effort = 54,600 should be able to pull about 55 cars. A USRA light 2-10-2, tractive effort = 69,400, about 69 cars. The 2-8-8-2, tractive effort, about 106,000, about 106 cars. And so on...

 

[Robert2d6]

The USRA 2-8-8-2 is setup the same way. The rear drivers are the only ones that are "powered". You won't notice only one set of drivers spinning unless you're starting out with around 40 or more (loaded) cars. If both sets of drivers were setup as "powered" then the number of chuffs per driver revolution wouldn't be correct.

I played around with making an e-spec that uses real world values for the USRA 2-8-8-2 today, and using it with the 2-8-8-2 I was able to pull 90 loaded 55-ton hoppers (and caboose) out of Princeton and up the .5% grade, which is the same number of cars that the real Virginian USRA 2-8-8-2 locos used to do on the same exact route.

So it looking like Trainz is capable of coming real close to matching the real world performance of steam locos. The old rule of thumb used by many U.S. railroads to roughly figure how many cars a given locomotive could pull was one 50 ton car for every 1,000 lbs. of tractive effort. So in other words, a USRA light 2-8-2 with a tractive effort = 54,600 should be able to pull about 55 cars. A USRA light 2-10-2, tractive effort = 69,400, about 69 cars. The 2-8-8-2, tractive effort, about 106,000, about 106 cars. And so on...

Ah, that is why I see all the drivers moving, very long loaded coal train I was pulling .....

 

[Robert2d6]

We are on the right track. I changed these values, went over 5 miles, including a stop to let an AI train go by for about 2 minutes, and a speed averaging 15 mph, and the safety valve was as quiet as a church mouse the entire way. Here is what I wound up with for engine spec settings.

USRA 2-8-8-2 TS12 Loco Kuid <kuid2:243294:1299:2>
Engine spec Kuid <kuid2:243294:1317:2>

Modifications to Engine spec in red.
steam


{
number-cylinders 2
number-power-strokes 2
firebox-heating-surface-area 31.99
boiler-volume 21.87
steam-chest-volume 0.6413
steam-chest-max-flow 240.09
max-fire-temperature 790
min-fire-temperature 600
initial-boiler-temperature 470.2
max-coal-mass 1215
ideal-coal-mass 608
shovel-coal-mass 24.3
safety-valve-low-pressure 1773
safety-valve-high-pressure 1809
safety-valve-low-flow 5.13
safety-valve-high-flow 15.4
water-injector-rate 8.48
piston-volume-min 0.015048
piston-volume-max 0.316015
piston-area 0.5361
burn-rate 1.026
burn-rate-idle 0.01026
speed 17.88
boiler-heat-loss 0.85
blower-max-flow 0.203
piston-angular-offsets 0.1,0.8854,1.6708,2.4562
firebox-thermal-conductivity 17
firebox-plate-thickness 0.019
super-heating-constant 100
firebox-efficiency 0.9
blower-effect 0.2
boiler-efficency 0.761
boiler-efficency-min 0.454
boiler-efficency-idle 0.667
valve-lap-percent 0.1
cutoff 0.55
hand-brake-max-force 5.9



Now anyone can download this loco from the DLS, which already has the engine spec in it, and then modify the engine spec. You have to remember every time you make a change in the engine spec, you have to delete the loco in your session and reinstall the loco in the session, before the new spec will take effect. After that, you can just load the same loco into any session. The silence from the safety valve is wonderful. In fact, in this screen shot about 6 miles out, I was waiting for an AI loco to pass, and it was going PHTRT..PHTTT PHHHTTT..PHTTTT PHTTT, and my loco was not making a peep. I could hear my fireman saying" I wonder who the jerk is in that loco"??????? :hehe:

Well this experiment in editing the engine spec on this loco from the original turned out to be a bust. I am using this on the Rogers Pass TS14 payware route, and there are some long 2-2.5 % grades on this run. I watched the boiler pressure drop and drop and drop down to at one point, around 90PSI. The train kept getting slower and slower and the only thing I could do was park, and wait for the pressure to build back up again with the blower on full. As soon as I would start, the pressure would take a dive again. My option were to start running diesel on this route which I did not want to do, or revert the engine spec back to the original, which is what I did. Now I have the screech of the safety valve again but that is better then running up a long grade at 8 mph, worrying about stalling all the way.

 

[wva-usa]

Well this experiment in editing the engine spec on this loco from the original turned out to be a bust. I am using this on the Rogers Pass TS14 payware route, and there are some long 2-2.5 % grades on this run. I watched the boiler pressure drop and drop and drop down to at one point, around 90PSI.

How many cars can you pull up this grade and what is the train's tonnage?

A 2-2.5% grade is a very steep grade for the mainline of a Class I U.S. railroad. I can't cite any real world examples of locomotive performance on the Rogers Pass but I can cite an example for the Virginian Railway on it's 13.4 mile, 2-percent Clarks Gap grade. The Virginian was using the largest steam locomotives in the world during the late 1910s through the 1920s and the trade magazines of the day featured numerous articles that detailed the Virginian efforts to conquer Clarks Gap grade.

In the 1920s, the Virginian was using one 2-8-8-2 Mallet and two of the even larger 2-10-10-2 Mallets (cut into the middle and end of the train) to move 5,500 ton (U.S., short tons) trains (about 75 50-ton cars) up Clarks Gap grade at a speed of around 8 MPH. The Mallets weren't speedy -- they were slow and methodical.

The train kept getting slower and slower and the only thing I could do was park, and wait for the pressure to build back up again with the blower on full.

You're describing (running out of steam) exactly what happened to the steam locomotives in the real world of the early-1900s that tried to climb a long, steep grade. The engine crew would have no choice but to stop the train and "blow up", i.e, build boiler pressure back up. That real world problem was common to the early 2-8-0 type locomotives, which couldn't support a large enough firebox and boiler to keep pressure up under extreme working conditions. The cure for the problem was a bigger firebox and boiler, which resulted in the 2-8-2 being developed which had a trailer truck to support the larger firebox.

In Trainz, the cure isn't that simple because there's no good way to really control how hot or cold the fire is burning to the same degree a skilled fireman could control the fire on a real steam locomotive. But from playing around with some e-specs during the past few days it seem apparent that if the boiler-volume value isn't close to the real world value that the Trainz locomotive will quickly run out of steam on long grades.

As soon as I would start, the pressure would take a dive again. My option were to start running diesel on this route which I did not want to do, or revert the engine spec back to the original, which is what I did. Now I have the screech of the safety valve again but that is better then running up a long grade at 8 mph, worrying about stalling all the way.

Try this engine-spec for the USRA Mallet. Using it, I have no problem running 90 car (empty) trains up the 1.5% grades on the Appalachian Mainline route, which is what the real Mallets of the N&W routinely handled on that same exact route. I can take 90 loaded 55-ton hopper cars up the .5 percent grade out of Princeton on the same route without a problem (just like the real Virginian Railway 2-8-8-2 locos were doing in the 1920s.)

The e-spec I linked to above can be adjusted easily -- just change the firebox-thermal-conductivity value. You don't need to change anything else. Firebox-thermal-conductivity is set at 17.67 in the file. If you want mo' steam, set it a little higher, such as 17.75 or so. If you want to use it with AI/DCC then you might want to set it at 17. I haven't had time to test it much with AI/DCC...

Load the firebox up with 120% or so worth of coal and it'll keep the pressure up on grades. Load the firebox up with 200% coal and the boiler pressure will stay below 240 while descending a long grade. It will develop the most pressure with a boiler filled with to 50-60 percent. If you add water to greater-than 60 percent levels the boiler can be cooled down a little. Running the blower will also helps the fire out...

 

[Robert2d6]

How many cars can you pull up this grade and what is the train's tonnage?

A 2-2.5% grade is a very steep grade for the mainline of a Class I U.S. railroad. I can't cite any real world examples of locomotive performance on the Rogers Pass but I can cite an example for the Virginian Railway on it's 13.4 mile, 2-percent Clarks Gap grade. The Virginian was using the largest steam locomotives in the world during the late 1910s through the 1920s and the trade magazines of the day featured numerous articles that detailed the Virginian efforts to conquer Clarks Gap grade.

In the 1920s, the Virginian was using one 2-8-8-2 Mallet and two of the even larger 2-10-10-2 Mallets (cut into the middle and end of the train) to move 5,500 ton (U.S., short tons) trains (about 75 50-ton cars) up Clarks Gap grade at a speed of around 8 MPH. The Mallets weren't speedy -- they were slow and methodical.



You're describing (running out of steam) exactly what happened to the steam locomotives in the real world of the early-1900s that tried to climb a long, steep grade. The engine crew would have no choice but to stop the train and "blow up", i.e, build boiler pressure back up. That real world problem was common to the early 2-8-0 type locomotives, which couldn't support a large enough firebox and boiler to keep pressure up under extreme working conditions. The cure for the problem was a bigger firebox and boiler, which resulted in the 2-8-2 being developed which had a trailer truck to support the larger firebox.

In Trainz, the cure isn't that simple because there's no good way to really control how hot or cold the fire is burning to the same degree a skilled fireman could control the fire on a real steam locomotive. But from playing around with some e-specs during the past few days it seem apparent that if the boiler-volume value isn't close to the real world value that the Trainz locomotive will quickly run out of steam on long grades.



Try this engine-spec for the USRA Mallet. Using it, I have no problem running 90 car (empty) trains up the 1.5% grades on the Appalachian Mainline route, which is what the real Mallets of the N&W routinely handled on that same exact route. I can take 90 loaded 55-ton hopper cars up the .5 percent grade out of Princeton on the same route without a problem (just like the real Virginian Railway 2-8-8-2 locos were doing in the 1920s.)

The e-spec I linked to above can be adjusted easily -- just change the firebox-thermal-conductivity value. You don't need to change anything else. Firebox-thermal-conductivity is set at 17.67 in the file. If you want mo' steam, set it a little higher, such as 17.75 or so. If you want to use it with AI/DCC then you might want to set it at 17. I haven't had time to test it much with AI/DCC...

Load the firebox up with 120% or so worth of coal and it'll keep the pressure up on grades. Load the firebox up with 200% coal and the boiler pressure will stay below 240 while descending a long grade. It will develop the most pressure with a boiler filled with to 50-60 percent. If you add water to greater-than 60 percent levels the boiler can be cooled down a little. Running the blower will also helps the fire out...

Thanks for the explanation, I tried the Beta spec this morning and it worked perfectly. Managed almost 20 mph up the same hill. It's a winner....

 

[wva-usa]

Thanks for the explanation, I tried the Beta spec this morning and it worked perfectly. Managed almost 20 mph up the same hill. It's a winner....

Cool! Were you able to keep it under control without it popping off?

 

[Robert2d6]

Cool! Were you able to keep it under control without it popping off?

After the climb of about 10 miles, I started down the other side at 1.5-2.5% down grade, and was getting some popping off , but that is to be expected I would think as much of the time the regulator was at zero. For some reason, the sound of the safety valve seems to be softer than it has been with other locos, so am not sure what happened there but I am not complaining.

 

[wva-usa]

After the climb of about 10 miles, I started down the other side at 1.5-2.5% down grade, and was getting some popping off , but that is to be expected I would think as much of the time the regulator was at zero. For some reason, the sound of the safety valve seems to be softer than it has been with other locos, so am not sure what happened there but I am not complaining.

Try loading up the firebox with coal, to 200%, when you crest the grade (or just before.) Doing that should lower the boiler pressure 10psi or more with a minute or so. Doing that lets me drift down the 1.5% grade from between Princeton and Glen Lyn on the Appalachian Coal route, which I think is around 15 miles (or maybe more) without the safeties lifting. The coal has usually burned down to around the 100% level by the time I reach the bottom of the grade.

 

[Robert2d6]

Try loading up the firebox with coal, to 200%, when you crest the grade (or just before.) Doing that should lower the boiler pressure 10psi or more with a minute or so. Doing that lets me drift down the 1.5% grade from between Princeton and Glen Lyn on the Appalachian Coal route, which I think is around 15 miles (or maybe more) without the safeties lifting. The coal has usually burned down to around the 100% level by the time I reach the bottom of the grade.

I will try that.

 

[Azervich]

Try loading up the firebox with coal, to 200%,

Cheers.

 

[wva-usa]

LOL, judging from the typical screenshot of steam locomotives posted here I think most people seem to believe that thick black smoke coming from a loco's smokestack was the norm for steam locomotives when in truth the goal of every good fireman was achieving a stack that was as smokeless as possible.

 

[Azervich]

There was a book I bought of ebay published 1952 and talks lots how to run a steam loco, fire temps, saving the coal on every 3-4 pages, operation of the stoker, injectors, sanders, cylinder drain cocks "actually says you have to have them open at all times when stationary and getting the train started to drain accumulated water that builds in the cylinders or it can cause the rods to bend and even crack a head"

This one you might like...

Cheers.