Soldier Summit SD40T-2 Independent Brakes

[OlPaint]

I understand that the brakes on the Soldier Summit SD40T-2 have been reworked. Is there a discussion somewhere about the proper operation of the brake system?
Also, has anyone noticed that the Independent Brake has a default application of 20% and that when the Independent Brake is released to zero application, it automatically returns to 20% application in the HUD and also in the control handle. What gives?

OlPaint

[ESzczesniak]

Page 10 of the manual:

http://railsimulator.com/support-assets ... l%20EN.pdf

Although any thoughts/input on a "normal" or "good" reservoir PSI drop would be helpful. I remember from the Canadian route that about a 6 PSI drop would be in the ballpark and further speed management could be with the dynamic brakes.

[OldProf]

Right, so the independent brake control lever sits near the cab floor at the rear of the control stand. If a keyboard control exists, it isn't mentioned in the manual. This means that in order to see or manipulate that lever with the mouse the engineer's camera has to be swiveled counter-clockwise and down, a position from which the brake gauges cannot be seen, much less the track ahead.

Simulation purists tell us to drive from the cab and avoid using either the keyboard or, heaven forbid, the HUD: just the mouse. To my way of thinking, that reminds me of Jackie Gleason's description of his golf game: "If I can hit it, I can't see it; if I can see it, I can't hit it." A real-world engineer would know just where to put his left hand to reach the independent brake lever without taking his eyes completely off the track, but as long as we simulators have only a fixed and rather poorly positioned camera dictating our point-of-view, I'll be pressing CTRL+Shift+1 to "bypass all [brake] scripting".

Incidentally, that 20% residual independent brake pressure doesn't seem to make much of a difference in driving.

[Chacal]

Have you tried the default TS2015 key for the independent brake?
The Driver's manual says “]”/ “[” – apply/release Locomotive brake.

Also the F3 and F4 huds have controls for the loco brake.
Are these not working with this engine?

[OlPaint]

Chacal

I have tried to use the keyboard "[" and "]" to release and apply the Independent Brake. But the moment I release the key, the Independent Brake returns to the default 20% application. It will not remain at the HUD position that I set it with the input. Very strange behavior?
How do I use F3 and F4 HUD for driving?

BTW, I yard shunt with the loco independent brake. The train brake is much too slow responce for shunting speeds.

OlPaint

[mrennie]

I understand that the brakes on the Soldier Summit SD40T-2 have been reworked. Is there a discussion somewhere about the proper operation of the brake system?
Also, has anyone noticed that the Independent Brake has a default application of 20% and that when the Independent Brake is released to zero application, it automatically returns to 20% application in the HUD and also in the control handle. What gives?

OlPaint

The advanced brake functionality and physics in the SD40T-2 include independent brake bail-off. If you move the independent brake handle in the cab to the left, you'll feel it stop at the Release position. If you let go of the mouse button for half a second and then continue dragging the handle to the left, it will move downwards into the bail-off position.If you release the mouse button, the handle will move back up and return to the Release position by itself - that simulates the fact that when you depress the handle (as in, pushing it down), it's done against the force of a return spring, so when you let go, it springs back up. That's how a real independent handle in a 26-L stand works.

The same happens when you use the F4 HUD or, indeed, the keyboard. The independent Release position is with the lever at 20%. Less than 20% means you're pushing down on the handle (bailing off) and if you let go of the HUD lever, it too will spring back up to 20%. Remember, 20% means that the handle is at Release. It doesn't mean you're applying 20% brake pressure. The brake pressure is linear, from 0psi to 65psi, between 20% and 100% on the lever (and the valve is graduated self-lapping).

Bailing off allows you to reduce the engine brake pressure without releasing the train brakes.

If you look at the F5 HUD, the "loco brake" value you see there indicates the independent brake cylinder pressure - 100% means 65psi. The pressure in the locomotive's brake cylinders also indicates by the "brake cyl" needle on the gauge in the cab.

[mrennie]

Right, so the independent brake control lever sits near the cab floor at the rear of the control stand. If a keyboard control exists, it isn't mentioned in the manual. This means that in order to see or manipulate that lever with the mouse the engineer's camera has to be swiveled counter-clockwise and down, a position from which the brake gauges cannot be seen, much less the track ahead.

Simulation purists tell us to drive from the cab and avoid using either the keyboard or, heaven forbid, the HUD: just the mouse. To my way of thinking, that reminds me of Jackie Gleason's description of his golf game: "If I can hit it, I can't see it; if I can see it, I can't hit it." A real-world engineer would know just where to put his left hand to reach the independent brake lever without taking his eyes completely off the track, but as long as we simulators have only a fixed and rather poorly positioned camera dictating our point-of-view, I'll be pressing CTRL+Shift+1 to "bypass all [brake] scripting".

Incidentally, that 20% residual independent brake pressure doesn't seem to make much of a difference in driving.

Actually, CTRL+Shift+1 doesn't bypass any scripting, it just sets the propagation delays to zero, so that the length of the consist doesn't make any difference at all to the braking. You'll still have the rest of the advanced brakes, including "peeing away your air", "bail off", etc.

Or you can change to Simple Controls mode.

The 20% on the lever means the handle is in the Release position, so if the train brakes are also released, you'll have 0psi in the engine brake cylinders (as see on the gauge in the cab). Moving the F4 HUD loco brake lever to less than 20% means you're bailing off (if you do it while looking at the handle in the cab, you'll see how it moves down against the pressure of the return spring).

[mrennie]

Have you tried the default TS2015 key for the independent brake?
The Driver's manual says “]”/ “[” – apply/release Locomotive brake.

Also the F3 and F4 huds have controls for the loco brake.
Are these not working with this engine?

Yes, the keys work perfectly.

[mrennie]

Chacal

I have tried to use the keyboard "[" and "]" to release and apply the Independent Brake. But the moment I release the key, the Independent Brake returns to the default 20% application. It will not remain at the HUD position that I set it with the input. Very strange behavior?

20% is Release. Less than 20% is independent brake bail-off, which is spring-loaded.

How do I use F3 and F4 HUD for driving?

The same way as you've always done, but you just have to be aware of the independent bail-off feature, and that the automatic (train) brake handle is scripted to simulate the effect of moving the handle up against the ridges in the brake quadrant that separate different zones - there are ridges at Release, Minimal Reduction, Full Service and Emergency. When you come up against a ridge, the script stops you from moving smoothly past the ridge but keeps the handle there until you let go for half a second and then continue moving. That's so that (a) you feel the ridges and (b) avoid going into an adjacent zone unintentionally (for example, it'll stop you from going all the way to Emergency when you only meant to do a Full Service application, or from going to Release when you meant to stop at Hold).

The HUD levers mimic the way the mouse-operated levers in the cab work.

BTW, I yard shunt with the loco independent brake. The train brake is much too slow responce for shunting speeds.

OlPaint

That's OK. The train brake is slower to respond because it relays changes in brake pipe pressure (at the head end) to the engine brake cylinders, and brake pipe pressure changes are slower than the rate of change that you can obtain using the independent brake.

It really depends on the length and weight of the consist you're shunting. If it's a long, heavy cut, you're probably going to need to use the train brakes, but otherwise the engine brakes can be sufficient to do all the braking you need.

[OlPaint]

Thanks everyone for taking me to school. I understand the way the train and loco brakes are supposed to work together now. Train handling is a lot more realistic in TS then moving the rheostat of a model train!!!

OlPaint

[mrennie]

Thanks everyone for taking me to school. I understand the way the train and loco brakes are supposed to work together now. Train handling is a lot more realistic in TS then moving the rheostat of a model train!!!

OlPaint

Thanks

I hope you have a go at using the brakes on 'hard' on the run down from Soldier Summit It certainly gave me an appreciation for the skill of real-life engineers.

P.S. Don't forget to use the dynamic brakes too.

[buzz456]

Mike,
Just let me take a minute to say once again what great contributions you are making to making this sim more realistic all of the time. I don't do much of the moaning about physics on here but I sure appreciate when you contribute what you do toward making them more prototypical. This is another major step forward.

[mrennie]

Mike,
Just let me take a minute to say once again what great contributions you are making to making this sim more realistic all of the time. I don't do much of the moaning about physics on here but I sure appreciate when you contribute what you do toward making them more prototypical. This is another major step forward.

Thank you Buzz, it really does mean a lot to me.

[buzz456]

Not to make too much of this but it may be the biggest thing since Krellnut's sound packages.

[mrennie]

Not to make too much of this but it may be the biggest thing since Krellnut's sound packages.

Maybe, but I should point out that the FEF-3 also has independent bail-off and train line propagation delay, plus it has all the brake rigging fully animated and the driving wheels actually lock up if you set the engine brakes too hard. On the other hand, the actual brake physics in the SD40T-2 are an improvement over what I did for the FEF-3, because I've done a more accurate simulation of train brake release, auxiliary reservoir recharge rate and pressure propagation, which you notice on long consists (so unless you put the FEF-3 to work on heavy coal drags, you wouldn't really notice the improvement).