Release & Running Positions - F7 Non Self-Lapping Brakes

[FHRob]

I just downloaded the F7-RW3_CMO file from the library.

This engine features reworked physics for the F7, including non self-lapping brakes.

I have a general idea about operating non self-lapping brakes, but I'm not sure of the difference - if any - between the release and running positions.

If somebody can post a simple explanation, would be appreciated.

Thanks!

Rob

[mrennie]

I just downloaded the F7-RW3_CMO file from the library.

This engine features reworked physics for the F7, including non self-lapping brakes.

I have a general idea about operating non self-lapping brakes, but I'm not sure of the difference - if any - between the release and running positions.

If somebody can post a simple explanation, would be appreciated.

Thanks!

Rob

In the real world, the running position slowly feeds the brake pipe with pressurised air to stop the pressure in the brake pipe from falling (slowly) and causing an unwanted/accidental brake application on the cars in the consist. In other words, "release" is to release the brakes, and "running" is to make sure they remain released.

[tbundy1982]

From what I remember from running an F7, there were more positions on the 24RL brake controller. From left to right: Quick Release, Release, Running, Lap, Full Service, Emergency. I don't remember where the handle-off position was. I just left the handle in release when moving. Putting the handle in Quick Release can overcharge the brake pipe, as it doesn't regulate the pressure to the feed-valve setting (it won't stop when it reaches 90psi like the release position). I know that Running works the way Mike explained on the old steam engine brakes. I also read somewhere that there was a position that would release the train brakes while holding the engine brake, essentially the opposite of bailing off the engine brake (I think this was called Running or Hold & I never tried to use it).
One flaw of the TS2015 game is that the Full Service position seems to always have a variable percentage value for application speed. From my memory, applying Full Service on a real locomotive just opens the brake pipe & allows pressure to vent. I don't recall the ability to adjust the speed at which the pressure vents, more like just on & off. The speed at which the brake pipe reduces is based upon the train length. I suppose with the limitations of the game, one could be mindful of the application percentage, using a higher percentage for short trains & lower percentages for long trains. Still, this is difficult to achieve when the engineer gets busy with other things.
Michael Stephen's modified brake physics on the F7 are better suited to longer trains. The application time is pretty slow on those units. Get 50 cars behind some F7's & it might feel somewhat realistic.
BTW- the new scripted brake physics in the new DTG releases are not terribly acurate either. I don't know that the script can assess the amount of cars in the train, so the new physics require the engineer to advance the difficulty level based upon the length of train they drive. A train of 20 cars probably has a response time similar to the default easy setting. I suppose a 200 car train might require the most difficult setting. If anyone has any suggestions on what settings seem appropriate for certain consists, please share!
I hope this was helpful in your understanding of how the 24 brakes work.
Tyler

[mrennie]

That's right, I was referring to the release and running positions of the automatic brake handle on a steam locomotive's 6-ET or 8-ET brake stand. Diesel locomotives do indeed have different stands that work differently.

That point of how the full application rate ought to depend on the length of the train line is addressed in my FEF-3, which also simulates the speed of the pressure wave so that there is a lag between the brake pipe pressure reading on the Head of Train Device (Wilma) and the head end brake pipe pressure indicated by the hand on the analogue pressure gauge. It also simulates the lag between that and the auxiliary reservoir pressure, that depends on train length. It also simulates, almost, engine brake bail-off. So even though the core simulation is flawed, there's still a lot that can be done through scripting to remedy some of it.