[pschlik]

railguy, on 09 June 2024 - 04:05 PM, said:

^I ran some experiments in NY MG R153 as you suggested. Most of my issues seem to be solved. It does appear that there has been modification (much needed) of how TrainPipeLeakRate works. One question that I have in the case of DPU locomotives: Does TrainPipeLeakRate only operate on the lead locomotive, or on the DPU as well--if the latter, would that make the leak rate additive? As originally implemented, it would seem that TrainPipeLeakRate was only effective on the lead locomotive, acting as a surrogate for the cumulative leaks in the train line. In real world operation, each car and locomotive would have its own leak rate, the total leakage of the consist making up the train pipe leak rate. Admittedly, such an approach would likely be "a bridge too far" in the sim.
Thanks to all who have worked on this feature. It's pretty neat to finally have DP locomotives having compressors, etc. doing things in the sim.

I expected the fix to train pipe leak rate would catch someone by surprise. Most folks didn't use it or set it to the usual 5 psi/min without a second thought. Anyone clever might have noticed that it didn't have enough of an effect on longer trains and set it to some unreasonably big number to get a visible amount of leaking. The implementation is still dubious as the leak rate is an engine parameter and not a wagon parameter-so the best I can do is take the leak rate defined in the player locomotive and apply that to the entire train. Other locomotives will have no effect. (Though this has the weird effect that the leakage can change when you switch cabs to a different locomotive.)

Leaks will need a major overhaul so that each train car can have its own leakage, preferably with some randomization and dependence on temperature, and that leaks for brake system components other than the brake pipe can be added. Brake cylinder leaks are particularly devious on the long mountain grades that MSTS creators loved to represent.

railguy, on 09 June 2024 - 04:05 PM, said:

A final question for Phillip. Can the "ORTSDPBrakeSynchronization ( "Apply, Release, Emergency, Independent" )" only be added to a locomotive's "base" .eng file, or can it be added to an .inc file that modifies the base .eng file?

Works the same as other parameters, functions the same whether placed in an .eng file or an .inc file. Just be careful to avoid including ORTSDPBrakeSynchronization in both the .eng file and an .inc file or else it will get hard to keep track of.

[railguy]

^Thank you for the answer. So, if I read your answer correctly, it the TrainPipeLeakRate is defined as "X" in an .eng file, the TrainPipeLeakRate in a 50-car train would be 50 times "X"?

I agree that defining a "TrainCarLeakRate" would be a more accurate way of representing reality. It would also allow simulation of what, in American railroad slang, is known as a "dynamiter"--a car with a leakage rate or brake valve malfunction significant enough that it reduced train line air pressure enough to cause an emergency brake application for the whole train--known as "dynamiting the train." When I worked in the railroad industry, people who didn't know railroad slang would sometimes get agitated when they heard a train crew tell the dispatcher over the radio, "This is Extra 123 West; we just dynamited at MP 302.6. The Conductor is walking back to try and find the dynamiter." It could often take a long time to find the "guilty" car, especially if the dynamiting was intermittent. Often, the "guilty" car would operate normally until the engineer made even a small reduction in the train line pressure, then the guilty car's brake valve would go into emergency, causing the whole train to go into emergency. That made for a long day for engineers, trainmen, and dispatchers.

[pschlik]

railguy, on 10 June 2024 - 09:08 AM, said:

^Thank you for the answer. So, if I read your answer correctly, it the TrainPipeLeakRate is defined as "X" in an .eng file, the TrainPipeLeakRate in a 50-car train would be 50 times "X"?

Sort of. If you have a leak rate of 5 psi/min on just the locomotive (ie: the way it was before), the actual leak rate you'd observe on the 50 car train would be something like 0.1 psi/min because there's so much air in the brake pipe that isn't leaking away. Now a leakage of 5 psi/min will actually show up as a 5 psi/min reduction in brake pipe pressure since all the air is leaking out equally. So it's not that the leakage is 50 times "X" but that it's no longer "X" divided by 50 like it used to be.

[ATW]

I have a few intentional BO (Bad Order) cars set to represent good knowledge check an demonstrations and a dynamiter is one but the leakage test, train check for BP continuity check without DPU providing air (check for middle closed angle cocks) is missing from having its own button cab options as well as cutting in/out Automatic brakes.

Currently in real operations when picking up dead or good power somewhere, the units picked up will always have a automatic brake cutin on one or many causing severe leaks, just won't pass an air test or if been sitting long shut down with main res leak to empty for leaks of Cylinders to show release where handbrakes held them

Since it sounds like a challenge to code and provide a cars with its own leak is there a starting point to allow ORTS E.O.T. device folder files to allow it? Those are the most leaking components. Average train I have with EOT conventional I either have the EOT released overcharged looking to show 92 on it or plain stuck at 89 like most leading locomotives.

[Weter]

Hello.
As I'm not aware about code writing, I can assume, that new leaks calculation approach seems to be better, than count every car's characteristic... at least - for the present moment - when non of *wag-files have leak rate parameter provided.
Thanks, Phillip for care about this side of pneumo-brakes physics.

[railguy]

I have done some additional testing with the "DP air synchronization" feature and I believe that there is one inconsistency with prototype operation that is significant. So, the TrainPipeLeakRate, as I understand it now, is "universal" across the whole train. In theory, then, the all of the locomotive main air reservoirs should be contributing air from their individual air reservoirs to replenish leaked train pipe air, which they appear to be. However, the "rub" is this, compared to prototype operations: In prototype operation, the restart pressure for the locomotive main reservoirs can vary by 1 to a few pounds of pressure. For example, with 3 lead locos, and 2 DP locos (5 total), the restart pressure in psi might be, say 133, 135, 132 on the lead locos, and 134, 131 on the DP locos. So, not all of the locos' compressors might start at the same time, or at all, depending on how quickly the train pipe pressure is restored. In my example here, Lead loco 2's compressor and DP loco 1's air compressor would start first. In the OR DP air synchronization regimen, at 135 psi, all 3 lead loco compressors start, and the both DP locos' compressors start at 134 psi.

Ideally, too, there should be a loco main reservoir leak rate specified in OR. Loco main reservoirs can leak independently of the train pipe, and most all loco main reservoirs have moisture ejectors that are ejecting some air regularly.

All of that said, I still think that the DP air synchronization is a cool new OR feature. Thank you.

[ATW]

That's true there are Main res leaks. I had 2 times have a DP in real life leak main res air and was are dynamiter when main res dropped bellow 90psi red on the screen while setting air, then we learned that it would not dynamite unless it was in run 1 or better main charged up beyond 120psi.

Any air system has its leaks whether bad hose or air tank. Just crazy when company wants you to pickup or take DB (Dead Bad) motors an those units have air issues to troubleshoot to pass air test.

[pschlik]

railguy, on 14 June 2024 - 02:13 PM, said:

I have done some additional testing with the "DP air synchronization" feature and I believe that there is one inconsistency with prototype operation that is significant. So, the TrainPipeLeakRate, as I understand it now, is "universal" across the whole train. In theory, then, the all of the locomotive main air reservoirs should be contributing air from their individual air reservoirs to replenish leaked train pipe air, which they appear to be. However, the "rub" is this, compared to prototype operations: In prototype operation, the restart pressure for the locomotive main reservoirs can vary by 1 to a few pounds of pressure. For example, with 3 lead locos, and 2 DP locos (5 total), the restart pressure in psi might be, say 133, 135, 132 on the lead locos, and 134, 131 on the DP locos. So, not all of the locos' compressors might start at the same time, or at all, depending on how quickly the train pipe pressure is restored. In my example here, Lead loco 2's compressor and DP loco 1's air compressor would start first. In the OR DP air synchronization regimen, at 135 psi, all 3 lead loco compressors start, and the both DP locos' compressors start at 134 psi.

In anything remotely modern, and by 'remotely modern' I mean 70s or later, the compressors are synchronized on all connected locomotives through the MU cable. If a single locomotive in the set decides that it needs air, all the other ones will be told to help repressurize even if their MR pressure isn't necessarily low enough to trigger the compressor alone. The only exception is that a locomotive will ignore the electronic compressor signal if its MR pressure rises 5 psi above the normal shut-off pressure. Normally there might be 1-2 psi of over pressure.