Steam Engine fuel consumption

[JimDep]

For steam engines, in general, which parameter(s) can I adjust in the engine specs to be able to go through coal and water faster than than what's it currently doing ? Overall, I'd like to get it to correlate also with having the boiler pressure go up when adding fuel, but I'll take it one step at a time.
Thanks

 

[2995Valliant]

Increasing the value of the burn-rate tag will make it burn through more coal. However in real life that will mean more steam is produced, and depending on who wrote the spec for Trainz you may have the same problem. You can counter this by reducing the max-fire-temperature and/or the fuel-energy tags.

Incidentally adding coal will cool the fire initially, so adding coal alone won't make the boiler pressure go up. Standing, it'll make no difference at all unless you have the blower on, working the engine hard you'll see the benefit some time after, depending on the size of the engine.

 

[JimDep]

Increasing the value of the burn-rate tag will make it burn through more coal. However in real life that will mean more steam is produced, and depending on who wrote the spec for Trainz you may have the same problem. You can counter this by reducing the max-fire-temperature and/or the fuel-energy tags.

Incidentally adding coal will cool the fire initially, so adding coal alone won't make the boiler pressure go up. Standing, it'll make no difference at all unless you have the blower on, working the engine hard you'll see the benefit some time after, depending on the size of the engine.

Thanks, I'll run some tests on this. Actually I'm using wood burning engines, but there is no script for woodburners, so I have to use whatever parameters that applies to coal. Normally, for one example, in real life, leaving the firebox door open when the engine is stopped with help keep the steam pressure needle down, but unfortunately that doesn't apply in Trainz.

 

[2995Valliant]

Depending the wood being burnt, it has a rough calorific value of 15000000 to 20000000 joules/kg, so unless you know what it is for the wood the loco used I'd go with a fuel-energy of 17500000, a max-fire-temp of 1000-1100 and as a starter, double the burn-rate from what it is on coal. Leave min-fire-temp where it is, and tweak the min-burn-rate so it maintains a sensible boiler pressure at rest.

A word of caution - all of the above is dependant on the rest of the numbers in the e-spec being fairly close to prototype. If it's one made using the Billegulla spreadsheet, (which was designed to give something which was easy to drive rather than any attempt at realistic performance) then you probably need to work out all the other numbers properly to get realistic performance.

 

[JimDep]

Depending the wood being burnt, it has a rough calorific value of 15000000 to 20000000 joules/kg, so unless you know what it is for the wood the loco used I'd go with a fuel-energy of 17500000, a max-fire-temp of 1000-1100 and as a starter, double the burn-rate from what it is on coal. Leave min-fire-temp where it is, and tweak the min-burn-rate so it maintains a sensible boiler pressure at rest.

A word of caution - all of the above is dependant on the rest of the numbers in the e-spec being fairly close to prototype. If it's one made using the Billegulla spreadsheet, (which was designed to give something which was easy to drive rather than any attempt at realistic performance) then you probably need to work out all the other numbers properly to get realistic performance.

Thanks for this great info. I'll start on this sometime tomorrow and post again on my progress. What is the Billegulla spreadsheet ? I'm not looking for something easy to drive, but challenging and realistic as possible when pulling passengers and freight up grades going up to 1.8%.

 

[2995Valliant]

Thanks for this great info. I'll start on this sometime tomorrow and post again on my progress. What is the Billegulla spreadsheet ? I'm not looking for something easy to drive, but challenging and realistic as possible when pulling passengers and freight up grades going up to 1.8%.

It was a spreadsheet designed to write an e-spec based on the parameters you entered into it. An awful lot of the assumptions it made for things like fire temperature were not based in reality, and neither was the performance of the resulting enginespec in the case of UK prototypes I'm familiar with.

It was simple though, and as a result was/is quite widely used.

Post the motor and steam containers here if you like along with some info in the real thing and I'll have a look.

 

[JimDep]

It was a spreadsheet designed to write an e-spec based on the parameters you entered into it. An awful lot of the assumptions it made for things like fire temperature were not based in reality, and neither was the performance of the resulting enginespec in the case of UK prototypes I'm familiar with.

It was simple though, and as a result was/is quite widely used.

Post the motor and steam containers here if you like along with some info in the real thing and I'll have a look.

Here's one of the engine specs I'm using.
I'm not sure which item listed is the " fuel-energy" to plug in the 17500000 that you suggested that I try.

description "Enginespec for woodburning 1869 Baldwin 2-6-0 Mogul
Boiler pressure: 130 psi
Cylinders: 16x24
Drivers: 48 inch
Tractive effort: 12,060 lbs

Created using the universal engine spec spreadsheet by Bill Fock"
kind "steam-engine"
category-region "US"
category-era "1860s;1870s;1880s;1890s"
trainz-build 2.9
category-class "ZE"

flowsize
{
trainbrakepipe 170000
epreservoirpipe 0.1
no3pipe 0.1
no4pipe 0.1
auxreservoirvent 0.1
auxreservoir_no3 0.1
auxreservoir_trainbrakepipe 0.1
autobrakecylindervent 0.1
auxreservoir_autobrakecylinder 0.1
equaliser_mainreservoir 0.06
equaliservent 0.06
equaliserventhandleoff 0.1
equaliserventemergency 0.1
no3pipevent 1.5
no3pipe_mainreservoir 0.1
compressor 5
trainbrakepipe_reservoir 1
trainbrakepipevent 0.06
no3pipe_autobrakecylinder 0.1
epreservoirpipe_autobrakecylinder 0.1
mainreservoir_ep 0.1
vacuumbrakepipe 0.1
vacuumbrakepipereleasevent 0.1
vacuumbrakepipevent 0.1
vacuumbrakereservoir_vacuumbrakepipe 0.1
vacuumbrakecylinder_vacuumbrakepipe 0.1
highspeedexhauster_vacuumbrakepipe 0.1
}

volume
{
scale 1
trainbrakepipe 0.2
epreservoirpipe 0.2
no3pipe 0.2
no4pipe 0.2
auxreservoir 0.038468
autobrakecylinder 0.009694
vacuumbrakepipe 0
vacuumbrakereservoir 0
vacuumbrakecylinder 0
mainreservoir 1
equaliser 0.5
independantbrakecylinder 0.010324
}

pressure
{
scale 1
compressor 0.009469
mainreservoir 0.009469
highspeedexhauster 0
brakepipe 0.005954
brakeinitial 0.005603
brakefull 0.003986
indbrakefull 0.003986
trainbrakepipe_start 0.004408
epreservoirpipe_start 0
no3pipe_start 0
no4pipe_start 0
auxreservoir_start 0.005041
autobrakecylinder_start 0.0049
vacuumbrakepipe_start 0
vacuumbrakereservoir_start 0
vacuumbrakecylinder_start 0
mainreservoir_start 0.008766
equaliser_start 0.004408
independantbrakecylinder_start 0.0049
}

mass
{
scale 1
fuel "6.2156e+006"
}

motor
{
resistance 1.7
adhesion 2.3
maxvoltage 600
maxspeed 25
brakeratio 100000
max-accel 4000
max-decel 20000
throttle-notches 16
axle-count 4
surface-area 80
moving-friction-coefficient 0.01
air-drag-coefficient 0.0002
driving-wheel-weight-ratio 0.9
}

steam
{
firebox-heating-surface-area 8.45
boiler-volume 2.06
steam-chest-volume 0.1095
steam-chest-max-flow 22.66
max-fire-temperature 738.5
min-fire-temperature 607.5
initial-boiler-temperature 449.5
max-coal-mass 373
ideal-coal-mass 187
shovel-coal-mass 10
safety-valve-low-pressure 1007
safety-valve-high-pressure 1028
safety-valve-low-flow 0.48
safety-valve-high-flow 1.45
water-injector-rate 0.9
piston-volume-min 0.003052
piston-volume-max 0.0641
piston-area 0.12972
burn-rate 0.315
burn-rate-idle 0.00315
speed 13.13
blower-max-flow 0.032
firebox-thermal-conductivity 17
super-heating-constant 100
firebox-efficiency 0.8
blower-effect 0.3
boiler-efficency 1
boiler-efficency-min 1
boiler-efficency-idle 1
valve-lap-percent 0.1
cutoff 0.55
piston-angular-offsets 0.0174,1.588
}

 

[2995Valliant]

That's a spreadsheet enginespec - the late Bill Fock was the author of said spreadsheet.

The fuel-energy tag should be in the steam container. It isn't, so Trainz will be assuming the default value of 31401000

In my opinion though, the only way you'll get realistic performance from that is to completely rewrite the motor and steam containers because almost every number in there will be wrong - even the boiler pressure.

 

[JimDep]

Can the fuel-energy tag just get added in, or will it be rejected or ignored ?
Unfortunately, I don't have access to the real numbers to rewrite the all the figures for the motor and steam containers.
Assuming the Trainz default uses the value of 31401000 for fuel energy, that means the 17500000 is a decrease of 55.73 %. Could that 55.73 % be applied to the rest of the existing figures to keep them all in proportion ?

 

[2995Valliant]

Yes it can be added in to the steam container.

As for increasing the other numbers in proportion I have think it's unlikely to work but as the numbers there are mostly just plucked out of the sky, it might! Finding the real world data is the trick.

I don't know about US protoypes, but there's a lot more info on the internet now for UK locos than there was 20 years ago. Even so I've amassed quite a collection of books over that time and learnt a lot in the process.

 

[JimDep]

Thanks, actually it would be a decrease of 56 % for all the other variables directly connected to fuel energy. I'll give it a shot.
I did a search for the Baldwin 2-6-0 Moguls for any year, and I couldn't find any info specific enough.

 

[2995Valliant]

Not sure I follow you there, but okay....have fun!

 

[JimDep]

Not sure I follow you there, but okay....have fun!

I'm not sure I'm following me either but here it goes.
Since the Trainz default uses the value of 31401000 for fuel energy, that means the 17500000 you suggested changing to is a decrease of 55.73 %. If the rest of the current parameters associated with fuel energy are based on the Trainz default, then would it make sense to decrease those by the 55.73 % too ?

Ya.......I don't know if I'd call this fun. I guess it's supposed to be.