Proper Bail-off

Discussion in 'General Discussion' started by kiski, Apr 3, 2020.

  1. kiski

    kiski Member

    Joined:
    Apr 27, 2018
    Messages:
    86
    Likes Received:
    54
    Hi all,

    I´d like to ask TS developers (if any of them even visit this forum), if it woud be a hard to implement a proper (mean - really working) bail-off for loco brake cylinders? We all know that all locos that simulates it just fake it - brake cylinder needle maybe drop to zero after you push the bail-off button or move the loco independent brake lever to correct position, but LocoBrakeCylinderPressureXXX controller still stays on the same value as TrainBrakeCylinderPressureXXX. Which means loco is still braked... It can be seen if you let ControlStateDialog window show up with game start.

    Thanks for the answer.
     
  2. JustWentSouth

    JustWentSouth Well-Known Member

    Joined:
    Nov 27, 2019
    Messages:
    1,103
    Likes Received:
    2,126
    The UP FEF 3 by Smokebox does just that! If you have a hard application and don’t bail off the independent, the locomotive wheels will skid.

    The Searchlight Simulations Canadian Pacific AC 4400 also has bail off and I’d be very surprised if it wasn’t properly reflected in the physics.
     
    Last edited: Apr 4, 2020
  3. kiski

    kiski Member

    Joined:
    Apr 27, 2018
    Messages:
    86
    Likes Received:
    54
    JustWentSouth : Sorry, but no. As I said, it is physically impossible to do that in TS2020, although the brake valve needle in cab show otherwise. No one can script it, not even Smokebox. Read carefully what I wrote previously. As long as train brake is applied, both loco and train valves are filled up proportionally to brake amount. Independet loco brake is "independent" as long as train brake is set to 0. If you don´t believe me, just switch game to windowed mode, add -- ShowControlStateDialog to launch options to the game and see it for yourself...
     
    • Like Like x 1
  4. kiski

    kiski Member

    Joined:
    Apr 27, 2018
    Messages:
    86
    Likes Received:
    54
    Because of how TS20XX handle the brakes - it consider whole train as one entity, so if you have only loco, then loco itsef is a train alone - maybe it would be sifficient, if there would be an option to modify MaxForcePercentOfVehicleWeight parameter in simulation blueprint for both TrainBrakeControl and for LocoBrakeControl. This way you could set it to 0 - wagons would be still braked according to amount of train brake applied, but loco would be released. I wonder if it would be hard to implement it - i guess not, we already have some blueprint parameters externalized - e.g. colour of lights, umbra, penumbra, RVNumber...

    So, developers - what do you say??
     
  5. Smokebox

    Smokebox Active Member

    Joined:
    Dec 10, 2016
    Messages:
    105
    Likes Received:
    98
    Yes, kiski is right about the fact that TS does not actually allow the simulation to cancel the braking effect of the engine/loco/independent brakes while the train brakes are still braking the train - that's because the coupling of the engine brake cylinder pressure with the train brake cylinder pressure is hard-coded in the TS core code, and there ain't nothing third party developers can do about it. It's actually stated already in the manual for the FEF-3, near the top of page 43:

    "Although it's still not simulated 100% (because if the train brakes are set, the locomotive, as well as the consist, is in fact still being slowed down), this implementation gives the closest approximation and feel of actual bail‐off that has ever been achieved in Train Simulator up to now."

    What that means is that unless you go to the trouble of watching the behaviour in the Control State Dialogue (which most people probably don't do), you would be unlikely to notice that the train was still braking just as much after bailing off the engine brakes. Apart from that, the rest of the functionality is simulated very realistically in the Advanced versions of my locos (as well as other locos that have my version of advanced brake scripting, such as the Sherman Hill diesels and UP GTEL), including the different positions of the engine brake handle, the spring-loading of the bail-off and quick-application positions, and the way that bailing-off is necessary to prevent the driving wheels from locking up and skidding under heavy braking.

    To address this issue would require DTG themselves to change the core code, which I honestly don't see them doing, because of the risk of breaking (not braking) existing DLC and scenarios. I fully understand that reasoning.

    By the way, as well as the FEF-3, the AT&N Consolidation also has the bail-off simulation. Both locos simulate a lot more besides just bail-off. For example, both of them show what happens when you leave the automatic train brake in Release for too long and overcharge the brake pipe, which leads to the train brakes being reapplied even though the gauges are showing that the brake pipe is fully charged (it's because when the brake pipe eventually leaks down from its overcharged pressure to the normal operating pressure, that drop in pressure is enough to activate the brakes). You have to know what you're doing to be able to handle the brakes properly in the Advanced versions.
     
  6. JustWentSouth

    JustWentSouth Well-Known Member

    Joined:
    Nov 27, 2019
    Messages:
    1,103
    Likes Received:
    2,126
    And that’s what makes driving your locos so much fun! Thanks, Smokebox. It’s now my goal to have every Fireman’s report read 0 seconds wheel skid.
     
    • Like Like x 1
  7. kiski

    kiski Member

    Joined:
    Apr 27, 2018
    Messages:
    86
    Likes Received:
    54
    Yes, Smokebox, I give you that - rest of your code is working nicely. Btw, I also have my own brake code version, where I simulate overcharged pipe as well - huge and long overcharging, and also a so called "linear decharge mechanism" - which just means that small overcharge will diminish in some time (normal value is 5bar, small overcharge is up to 5,8bar, big one is everything above that)...and much more. Atm I´m working on touch display for loco control system...
     
    • Like Like x 1
  8. Smokebox

    Smokebox Active Member

    Joined:
    Dec 10, 2016
    Messages:
    105
    Likes Received:
    98
    Sounds excellent! It's good to see more people implementing clever ways of increasing the realism of TS.

    My overcharging simulation also does the discharge over time (so that it leaks down to the maximum pressure set by the system regulating valve - another part of the code detects that and causes the corresponding application of the brakes on the cars).
     
  9. kiski

    kiski Member

    Joined:
    Apr 27, 2018
    Messages:
    86
    Likes Received:
    54
    By Linear Discharge Mechanism (LDM) I meant a small discharging over time like you, but LDM do not cause any reaction of the brakes on the cars. They run normally, just overchraged air leaks out until normal state is obtained again (5bar in Europe).
     
    • Like Like x 1
  10. Smokebox

    Smokebox Active Member

    Joined:
    Dec 10, 2016
    Messages:
    105
    Likes Received:
    98
    Ah, I see, it's a clever real world system for dealing with overcharge :)
     

Share This Page