F7 Repaints: TS2012 Updates Out Soon!

[Griphos]

By "straight air", Kali, you mean the independent, or engine, brake?

[Kali]

Yes, the independent brake, sorry - they call it "straight air" over here because it just plugs the air reservoirs straight into the brake cylinders; originally our diesels had self air-brakes and vacuum train brakes all worked through the same distributor, which altered the timing of the locomotive brakes somewhat as it mimiced the vacuum. Actually it still does now they've got train air brakes anyway.

However it should work very fast, as you'd imagine.

[tbundy1982]

It seems that the "straight air" technique only works well in some situations. The real problem with most simulators that I'm aware of is that the independent brake and bail-off function only apply to the lead unit, not all the units that are coupled and connected with multiple-unit (MU) controls. Where I live in the midwest, the CN uses two former IC GP38-2s back to back and MUed together. This effectively doubles the locomotive braking power and can be used to "kick" cars.

I know that with MSTS, only the first unit in a player consist would get the independent brake applied to it's physics, and the same scenario with the bail-off function. Trailing units act like boxcars. "Boxcar" is a term when a locomotive is towed in consist without the MU control of its brakes engaged. This effectively makes it a (heavy!) boxcar, responding only to the automatic brake.

The above being said, using one unit for switching small consists would allow one to use the independent brake realistically. Using two or more units in a consist has appeared to me to result in decreased braking effort with the locomotive brakes, likely because only the first unit is actually braking. I know that the automatic brake is used when switching on the road because the air brakes are already made up on the train and it does offer better control with longer and heavier cuts of cars. I'm sure that in some areas where a steep grade might cause an issue, yard switching may also be required to be done with automatic brakes in order to safeguard against runaways.

Michael, when you say 60 seconds to a 50psi brake cylinder charge, what is your brake pipe PSI reading? I usually judge all of my air brake work on train-line levels. It's been a long time since I've used a 24 brake, but IIRC, 10-15 seconds should drop 10 psi at the brake stand. I wasn't using it on long trains, 5-30 cars. Maybe it reacts differently with a longer train. I know that a longer train will take longer to set up at the rear car, but I don't know if it takes longer to drop pressure off at the brake stand.

Also, the 24RL brakes I've used did not have a pressure maintaining feature, meaning that a leak in the brake pipe could cause your 10 PSI reduction to continue to slowly reduce even more as air leaked from the pipe. A bad triple-valve could do the opposite, letting air from the reservoir back in the brake-pipe and slowly releasing your brakes. The 26L brake stand like you see on the SD40-2 has the pressure maintaining feature and, therefore, will compensate the brake pipe pressure to keep it reasonably steady.

Again, long on theory, short on real world experience...

[Kali]

I did test the independent brake - I forget the results now, but I think it did not actually propagate. I remember this because I tried to set it using scripting and it wouldn't set there either. This is prototypical for the UK at least ( and I think Europe ) but not over there obviously. There's no facility for manual bail-off, I think there's some setting for auto bailoff but I've no idea if it works.

The way to do it for a pure US yard switcher would be to borrow the vacuum brakes and with a bit of trickery you can make the cab needles move right. It wouldn't work any air autobrakes obviously - if you made it dual brake then you're using the whole consist instead of just the engine.

Simple answer; make the indy brake stronger.

[Chacal]

I'm slowly getting the hang of it, even though poor passengers sometimes have to walk a mile or so to get back to the platform.
Any application below 88% is pretty much useless, apart maybe for maintaining speed in grades.
My main problem is that it is easy to tap the key once too much and go into emergency, and then you can't cancel and have to watch the brake cylinder pressure slowly go all the way up, then all the way down.

[GreatNortherner]

Hi,

Thanks for your replies. I got some good news -- the loco brake should be working on all (head end) engines once we complete the patch. The currently available units have a BIG flaw here -- I accidentally linked the default engine script, so on the dynamics/loco brakes still work only on the lead engine. That will change with the next update!

It seems that the "straight air" technique only works well in some situations. The real problem with most simulators that I'm aware of is that the independent brake and bail-off function only apply to the lead unit, not all the units that are coupled and connected with multiple-unit (MU) controls. Where I live in the midwest, the CN uses two former IC GP38-2s back to back and MUed together. This effectively doubles the locomotive braking power and can be used to "kick" cars.

GREAT!!! This is what I needed to know, I always wondered how the US railroads handle the braking when switching cars. So short cuts of cars -- loco brakes. Long cuts -- train brake, am I going in the right direction with this assumption? How would the engineer avoid depleting the reservoir when having to "stop and go" move a long cut of cars? Would the engineer in some situations maybe even keep the brakes applied while moving the cars, to save pressure?

Michael, when you say 60 seconds to a 50psi brake cylinder charge, what is your brake pipe PSI reading? I usually judge all of my air brake work on train-line levels. It's been a long time since I've used a 24 brake, but IIRC, 10-15 seconds should drop 10 psi at the brake stand. I wasn't using it on long trains, 5-30 cars. Maybe it reacts differently with a longer train. I know that a longer train will take longer to set up at the rear car, but I don't know if it takes longer to drop pressure off at the brake stand.

Again, thanks a lot! This is invaluable information to me, as my real world experience about this is zero and my theoretical knowledge quite limited, just the stuff I picked up playing MSTS and reading Al Krug's website. I need to check the brake cylinder to brake pipe pressure readout, but if memory serves me right that was always pretty spot on 2 to 1 in Railworks.

Thanks,
Michael

[Kali]

2.5:1 for US, it's there in the blueprints somewhere. I think the recent setups use distributors in the blueprint for engines - while that's not technically correct it makes the things *work* more correctly so I've just left them alone. Just think of it as a better defined triple valve.

[tbundy1982]

So short cuts of cars -- loco brakes. Long cuts -- train brake, am I going in the right direction with this assumption?

I should also add that weight is the most important factor in determining what consist can be handled with which type of brake. The ability to handle a long cut can be significantly more challenging with loaded cars rather than empties. For a quick calculation, using 64,000 lb (tare) covered hoppers, a 100 car train of empties would weigh 3200 tons, while 100 loads would weigh between 11,000 and 13,000 tons. That's a big difference!

I remember we would take 4 GP10's out to switch and they could handle 100 empties using just the engine brake. The slack action and resulting sounds can be explosive! The 4 locos could usually stop the empties within a few car-lengths, maybe 150ft. You would not want to be riding the end of that car when the slack ran out!!! Bang!!! It could throw you right off!

We could control 15 loads at slow speeds with a single GP9. Usually, though, when making a stop with loads, the auto brake was used for better control. You wouldn't want to try to stop 15 loads at 10 mph with just the engine brake. It could be done but was not nearly as efficient as using some auto brake. Sometimes we would "kick" cars in the yard, but it was a very rare occasion and would usually use 3-4 men on a crew to accomplish it. To do this, all of the cars had their brake systems bled off and would roll freely when uncoupled. The engine would shove hard on the cut, then stop quickly when signaled and the conductor would lift the pin where the cut was to be made as the slack began to run out. As the locomotive and connected cars stopped, the disconnected cars would roll down into the yard and couple to the existing cars in that track. There would be a switchman lining the movement and a man down in the yard making sure all of the cars coupled together and there were no roll-backs. Labor intensive procedure, but very time efficient.

Would the engineer in some situations maybe even keep the brakes applied while moving the cars, to save pressure?

Well, it depends on the size and weight of the train. In most cases, you would fully release the brakes of the cars before trying to move them. Maybe on a serious grade, the method would be to release the engine brakes and use a little power to get them moving but under control.

A version of this technique would be setting the retainer valves on individual cars to control braking on the way down the grade. I never had to use retainers, but from what I remember they would be used to hold the pressure in the brake cylinder of a car while the train brakes were released. Setting a retainer every few cars throughout a train can let you release the train brake and have it charge while not risking a runaway, plus you can get the extra bit of control by also re-applying the brakes on the other cars when necessary. Of course, the train would have to stop at the bottom of the hill and the conductor and brakeman would have to walk the length of the train manually releasing the retainers throughout the whole train. This time consuming process is still considered valuable because of safety benefits of using retainers.

In my humble opinion, a great part of realistic train operations is missed in all of the train simulators by not providing a tonnage report on trains at any requested time during play. I can't imagine that feature would be difficult to include, but I don't make train simulators so I can't say for sure. The benefit of this small amount of information is that one can test theories of train handling in even more precise conditions. Some routes have tonnage limits on specific grades, and some routes have tonnage limits for the horsepower provided. The addition of this feature could help activity creators and average players alike, along with providing another strongly necessary variable for those testing and tinkering with game physics.

Thanks to you, Michael, for making some fantastic equipment and routes for all of us to enjoy. I'm always looking forward to the next thing you have up your sleeve!
Tyler

[Griphos]

Now that is a fascinating and very informative post. Man! Thanks for taking the time to share that kind of professional knowledge with us.

[Machinist]

Now that is a fascinating and very informative post. Man! Thanks for taking the time to share that kind of professional knowledge with us.

Amazing indeed, especially to me a VORA engineer (as Griphos as well)... I'm saving this to be used with TS2014 (sic, or RW5 ) when physics, by default, will be hopefully closer to prototypical.

@Tyler: It seems you are not aware yet, but other trainsims show tonnage of consists (one of them at any time whilst playing), that's is missing only in RW3.

[Kali]

It's in RW3, it's just a script call ( GetConsistWeight? I think ).

[tbundy1982]

Kali, is there a more detailed way for us to access and use this feature? Scripting and coding is a foreign language to me.

Glad I could offer something useful. I'll try to help if I know the answer to a question or where to find that answer.

I don't believe we have working retainers in TS2012 (or I just don't know how to use them yet...). A workaround would be to set handbrakes every 5-6 cars before starting down a stiff grade.

For example, if your train went into emergency coming down Cajon Pass, if you simply released the brakes and took off, your train would have no brakes left when an application was needed. Walking the train and setting handbrakes would allow the engineer to release the brakes, get a full charge of the brake pipe, and then make an application to hold the train while the handbrakes were released. It is much quicker for a quartet of GEVO's to recharge a 15 PSI reduction than a 90 PSI emergency application. Plus, as each handbrake was released, the retainer could be set on that car at the 15 PSI reduction so as to partially replace the force holding the train steady. A hand brake can be applied pretty tight, like 95% or more of an individual car's braking ability, especially when it is applied when the car is in emergency. A basic 15 PSI reduction of the brake pipe would have far less braking effect. Retainers use the braking effort of what is currently applied on the car, not it's maximum braking capacity. I haven't practiced this technique so it is only theory. Perhaps a more experienced mountain railroader could elaborate on this more?

I wish I had more solid experience to add. Running trains above 20-25 mph would add a bunch of other techniques that I just don't have in my experience bank. At 20 mph, you could usually stop a train within 1/2 the range of view.

Mountain railroading is a different beast altogether...

We have gotten a bit off track from F-Units here. I'm going to download a set now and give them a try myself.

Tyler

[Shayfan1]

Hey yall if I provide some pictures can anyone do a Western Maryland F7 in both Black Speed Lettering and Circus Colors scheme. This would be a really nice addition to the game thanks.

[Kali]

Kali, is there a more detailed way for us to access and use this feature? Scripting and coding is a foreign language to me.

Not really, no. The nearest you could get would be some sort of cab readout, but not only would you have to fiddle with the engine script you'd also have to do the 3d work for the cab model! the issue isn't the script part - I could give you a copy & paste code snippet to do that - it's what you do with it afterwards.

RW has blueprint entries for retainers, but I've no idea if they do anything. I can't think of a way you'd set one anyway.

[GreatNortherner]

Hi,

Again, thanks for your very helpful and enlightening post! This is all very good to know and invaluable information for the physics tweaking process. Also I don't think this has veered off from the discussion about the F7s, their (slightly messed up by me) physics update was after all an integral part of the set.

Though I should add, I doubt Railworks will ever be as detailed and spot-on as, physics-wise, for example, Open Rails (ORTS) is in conjunction with fine-tuned MSTS car physics (as 3rd party mods!). In my opinion it's just a totally different kind of animal, and I doubt most casual users would even care for such advanced and "ultra realistic" features -- these can make the 'game' quite tough and even a bit frustrating at times, like waiting for the reservoirs to recharge after an emergency application. However, most of what you described as missing from RW is actually already available in MSTS with Bin-Patch, or also in ORTS, both of which have a massively detailed HUD. Brake force, brake pipe/cylinder pressure, reservoir pressure -- all listed per engine/car, for the entire train. Bail off engines, no problem. Brake pressure also propagates along the train. The HUD also gives you readouts for in-train forces, slack, wheel friction, and much more I can't remember right now.

Cheers,
Michael