Locomotive control stand brake pressure gauges

[PapaXpress]

I am working on an accelerometer. What I am lacking is how often it updates (every second, every 5 seconds?).
Air flow... I have one, but its kinda working. For now I am saying its a show piece.

And yes, its all LUA.

@Rich, RW can use a dynamic brake chart which accurately describe its behavior. I was able to translate the GP40-2 DB chart from the service manual to RW and it have a really good feel when using it.

[_o_OOOO_oo-Kanawha]

I am working on an accelerometer. What I am lacking is how often it updates (every second, every 5 seconds?).
Air flow... I have one, but its kinda working. For now I am saying its a show piece.

And yes, its all LUA.

I figure polling speed every 5 seconds should be enough to provide an indication of change by acceleration. There is already quite some flutter in the zero speed when the train is standing still. The HUD shows EOT speed, I assume the SpeedoMeterMPH controlvalue shows the locomotive speed.

Airflow: since the brake pipe empties and fills so fast in Railworks, it is just eyecandy, as there are no leaks either.

[BNSFdude]

Airflow: since the brake pipe empties and fills so fast in Railworks, it is just eyecandy, as there are no leaks either.

Have you seen the Class 66v2? They have a gauge that shows Airflow.

[PapaXpress]

I finally have the locomotive brakes working properly. The trick will be not to use the HUD since they are not mapped to my virtual controls but the controls I am manipulating under the hood.

[_o_OOOO_oo-Kanawha]

Will manipulating the handles in the 3D cab work the brakes as intended? The HUD is disconnected from the handles in the NW SD45 as well because of the Traction/Brake selector which is programmed in lua.

I suppose that will make RailDriver compatibility an issue?

[PapaXpress]

Yes, I have the handles working properly. Now I am making sure that basic mode works. Its my hope that RailDriver will operate correctly under basic, since there is no chance for it work for expert.

I say hope because I do not own (nor can I afford) RailDriver.

And before anyone offers their services to beta test, please accept my apology but, no thank you. We already have our own plans for beta.

[_o_OOOO_oo-Kanawha]

So the air brakes are covered. Good.

Now the ammeter, ideally it should show the maximum current at the speed and tractive effort indicated in those tables per engine, i.e. 1050 Amps for 54700 Lbs at 10 MpH for NS GP40's. Dynamic braking ditto, plus notch 1 on the Diesel for excitation and higher notches for cooling the traction motors, if the blowers are driven off a PTO on the crankshaft.
Few, if any Railworks US Diesels, have a correct ammeter. The current flows as soon at the generator is engaged, before the engine starts to move.
I suppose that means more lua scripting then?

And no, I am not fishing for a free ride. This topic only helps me in tweaking the locomotives in my copy of Railworks for a more prototypical behaviour, even if it is only eye- and earcandy. Changing core parameters usually breaks a scenario.

[PapaXpress]

Where are you reading about these GP40 behaviors? I am getting different information about how the HP and RPMs should be when under 24 MPH.

Besides. I don't think we can alter the amps too much. Sure we can read it, and then alter the needle, but we could be way off too easily. I think the values we are getting from the game core are close.

I still need to look at the DB meter, but I can't find any information where (with a standard DB) the needle would not be in direct relationship with how much resistance you are applying. So its almost a 1 to 1 relationship between the handle and the needle. This is a case where its not too much use because we can't simulate if something happens in the grid.

[_o_OOOO_oo-Kanawha]

Papa, I got those NS GP40 values from the 2006 Locomotive Engineer Training workbook I linked a few post up, page 168. One shound assume 62:15 gearing (for 65 MpH max?), and standard DB, at least on NS. The GP40-2 maximum tractive current isn't given, but is has slightly less TE while it is heavier (?). Important distinction, is has standard tapered DB, the different characteristics are explained. Both units have composite brake shoes, hence only 45 Lbs max brake cylinder pressure.

CSX's table isn't as detailed, but it lists GP40's continuous speed as 12 MpH and differentiates between Standard and Extended DB on the Dash 2.

Since I found those manuals, I have plundered several other websites and collected a few dozen more of various kinds and thoroughness. Need to sort all the information out and digest it.
Not that it makes much difference when the particular instrument or control cannot be disconnected from the simulation engine in Railworks, but inquiring minds want to know.

[Rich_S]

So the air brakes are covered. Good.

Now the ammeter, ideally it should show the maximum current at the speed and tractive effort indicated in those tables per engine, i.e. 1050 Amps for 54700 Lbs at 10 MpH for NS GP40's. Dynamic braking ditto, plus notch 1 on the Diesel for excitation and higher notches for cooling the traction motors, if the blowers are driven off a PTO on the crankshaft.
Few, if any Railworks US Diesels, have a correct ammeter. The current flows as soon at the generator is engaged, before the engine starts to move.
I suppose that means more lua scripting then?

And no, I am not fishing for a free ride. This topic only helps me in tweaking the locomotives in my copy of Railworks for a more prototypical behaviour, even if it is only eye- and earcandy. Changing core parameters usually breaks a scenario.

2-8-4 Berk / Kanawha, I think you are getting confused. The amps you read on the ammeter are related to the work the engine is doing, regardless of engine speed. Notch one stall current will be about 300 amps and notch 8 stall current will be 900 to 1200 amps, but once everything is moving, I can cruse at 10 mph notch 1 with only 100 amps on the ammeter. Plus the current is not instantaneous, you can watch it slowly build up on the ammeter. Also on EMD locomotives, the diesel engine does not have a PTO, it has a auxiliary drive shaft that runs the Aux Gen and the traction motor blower is directly connected to the Aux Gen. The Traction Motor blower is a squirrel cage type blower.

Regards,
Rich S.

[Rich_S]

Both units have composite brake shoes, hence only 45 Lbs max brake cylinder pressure.

I think you are still confused on the brake cylinder pressure. The brake shoe does not determine the pressure and in fact all brake shoes today are composite. The brake cylinder pressure is determined by the number of shoes per wheel.

Look closely at the wheels on the 3005, you'll notice a brake shoe in front of and behind the wheels. This unit will have a maximum brake cylinder pressure of 45 psi.

ns3005.jpg

Now look closely at the wheels on the 5504. Notice that each wheel only has one brake shoe, so the brake cylinder pressure on this locomotive will be 72 psi.

ns5504.jpg

Hope this helps?
Rich S.

[_o_OOOO_oo-Kanawha]

Thanks, Rich, for pointing this out. It is mentioned in the training manual. Guess I'll not make a good engineer then.
Good to hear you are an engineer. Your knowledge and experience will be most helpful to Papa and his crew. Glad you share it with us here as well.

Single side brakes have a higher cylinder pressure than double sided "clasp" brakes. Makes sense because a single brake cylinder actuates all brake shoes on each axle and the brake shoes have to do the actual retarding without stalling the wheel.
Guess that engineers on many roads that acquired same units from different predecessors through mergers have to acquaint themselves with each consist anew everytime they are called.

I have not noticed any real dependance of indicated traction motor current on load/exercised tractive effort. Guess the simulation engine is at fault here as it all seems to depend on those curve file instead of actually being computed.

Concluding, I think this thread has run its course and I have found lots of interesting information and documents.
Everything has been covered: instruments and controls. Now it is up to the builders to create engines that operate and look as realistic as Railworks allows even if only to please the eye.

[Rich_S]

Thanks, Rich, for pointing this out. It is mentioned in the training manual. Guess I'll not make a good engineer then.
Good to hear you are an engineer. Your knowledge and experience will be most helpful to Papa and his crew. Glad you share it with us here as well.

Single side brakes have a higher cylinder pressure than double sided "clasp" brakes. Makes sense because a single brake cylinder actuates all brake shoes on each axle and the brake shoes have to do the actual retarding without stalling the wheel.
Guess that engineers on many roads that acquired same units from different predecessors through mergers have to acquaint themselves with each consist anew everytime they are called.

I have not noticed any real dependance of indicated traction motor current on load/exercised tractive effort. Guess the simulation engine is at fault here as it all seems to depend on those curve file instead of actually being computed.

Concluding, I think this thread has run its course and I have found lots of interesting information and documents.
Everything has been covered: instruments and controls. Now it is up to the builders to create engines that operate and look as realistic as Railworks allows even if only to please the eye.

Glad to help, although I'm not a engineer I'm a locomotive electrician. I get to fix these things when they break, then I get to test them on our test track When it comes to operating the locomotive from the engineers standpoint, single brake shoes operate the same as double clasp brake shoes. All locomotives have 45 psi in the brake valve, on locomotives with single shoes there is another valve that increases the pressure to 72 psi. The biggest difference for the crew is the sticker in the cab that either reads "Maximum brake cylinder pressure 45 PSI" or "Maximum brake cylinder pressure 72 PSI", everything else is the same.

Rich S.

[arizonachris]

*snip* I'm a locomotive electrician. I get to fix these things when they break, then I get to test them on our test track

Rich S.

Little off topic but that sounds like a job I would love to have, Rich!

On Topic, this has been a very interesting discussion to read. A member named "Kali" was working on braking dynamics a while back, not sure where he disappeared to, maybe Run 8 which I hear has better modeling of braking.

Me, I just like to drive 'em. Guess I just put up with the inaccuracies, not having ever driven any type of locomotive or engine in real life, so I just figure it's a different beast each time I jump into a different cab. It all seems to be realistic enough to me I suppose.

[PapaXpress]

Kali left well before Run 8. I am not sure what happened to him. I have used much of his research when designing the scripts for the GP40.