Tweaking braking for an enginespec - guidance needed.

[AlexMaria]

Hello all,
I'm in need of some guidance related to "tweaking" the breaking performance for some of my content.

As you may know, 95% of my content revolves around relatively-modern electric multiple units, something that trainz's enginespec system (seemingly, and likely, designed around diesel locomotives and heavy freight trains) does not seem to "digest" very well, leading to "poor" performances in terms of realism.

While i've managed some work-arounds for the "traction" part (especially eliminating the annoying wheelslip) chiefly thanks to the nice "edit power curve" function of the content manager test track fetaure and a copious use of the "maximium tractive effort" tag with a ludicrous value, i'm still stuck with the braking part - no matter what i try, wich values i change, i can get one of two only results - either the brake performance of a fully loaded 3000t-heavy US freight train on a subway MU or a absolutely irrealistic "stopping-on-a-dime" performance, where the minimum brake notch will halt your train within the space of 100m.

Problem is, that unlike for the "traction" part, with it's neat and handy "edit power curve", there isn't an equivalent tool for braking and worst of all, the Trainz Wikibook is less than useful, as the "Pressure", "Flow" and "Volume" tags pages (wich are the ones influencing braking performance) from the "KIND Enginespec" entry either have "TBD" as description, or outright look like this:

I would greatly, greatly appreciate if someone could shed a light on the less-than-straightforward braking configuration system trainz uses.

Fundamentally i don't need a complete walk-trough of all the tags (even if i would greatly appreciate it), at the bare minimium i just need to know wich values do i need to modify (and how) to:

A) "tune" the application delay (e.g. i move the brake lever into the given position, and the brake pressure starts increasing after XYZ time).
B) "tune" the braking force so that it can be "eyeballed" up to a given decelleration rate, so as that you don't get either the afromentioned "stopping-on-a-dime" nor the braking performance of a fully loaded 3000t freighter.
C) "tune" the time needed to increase and decrease pressure from one given application step, to another or to release - on "normal" trains this of course depends on the lenght of the train and the fact that braking is controlled by the locomotive - on EMUs however, especially subway, subway-like and light rail trains, braking is controlled electrically from all vehicles, and as such pressure increases and decreases are nearly instantaneous, and as such, the braking performance remains virtually unchanged at different lenght.

Furthermore, as mentioned, 95% of my content revolves around relatively-modern electric multiple units, all of wich use electro-pneumatic braking and have a much "smoother" braking operation, with each braking notch gradually increasing and then holding pressure, rather than the "straight air brake" (release-hold-apply-lap-emergency) system trainz "seems" to prefer - "seems" because while the "labels" are the same, some locomotives and MUs will behave closer to an EP-braking systems, and others closer to the straight-air system, and this seemingly random and irrespective of the system used on the actual rolling stock (e.g. i have a few current-era EMUs, from other content creators, that behave exactly with a straight-air-brake system). Wich value(s) in the enginespec file "braking section" causes this "switch" in behaviour?

Addendum: all of the above is relevant for cab mode - i have essentially no issues with CCD mode.

Thanks in advance for helping!

 

[2995Valliant]

You probably need to edit the "brakeratio" tag in the motor container. It should be between 50 and 65% of the relevant vehicle's mass - probably the high end of this for modern air-braked stock.

I have only recently latched onto this for my UK engine specs, and it makes a huge difference - controlled stops are now possible!

I've now got to update 200 or so enginespecs, and persuade rolling stock creators to adopt compatible specs for the UK as obviously the change needs applying to all vehicles in the train to see the benefit.

 

[EverTrainz]

persuade rolling stock creators to adopt compatible specs for the UK

FWIW it may be possible to do this without having to beg, plead, or otherwise go on wild goose chases.

There is a script function:
SetEngineAsset()

… which allows you to change the enginespec for a given vehicle in a session.

An implementation would probably have to be done on a separate placeable “physics asset” that runs its script and changes enginespecs for all vehicles* on a given route/session once placed, without having to touch the vehicles’ native scripts. But it would effectively allow you to use an extensions table in the config to assign your new proper especs KUIDs corresponding to loco/coach/wagon KUIDs that have inaccurate specs.

* = all vehicles listed in the Physics Asset’s extensions table

EDIT:
Or it could also be done as a session rule thing. Never messed with those though so I’m not 100% sure.

 

[edh6]

You can change the spec a vehicle uses on a per session basis using the vehicle's properties dialogue.

 

[EverTrainz]

Doing it for a lot of vehicles manually would get tedious on larger routes though I assume.

 

[PortLineParker]

The other thing that needs to be considered is that a lot of rolling stock, in particular locos and tenders, have incorrect mass values as well as queue loads. Locos, carriages and wagons are often heavier or lighter than they are in real life and no espec can change this as it needs to be changed in the asset's config. With Packaged content in particular this cannot be done so would need to be updated by the author, as would any coal and water queues that are wrong.

Anthony's work is second to none and he puts a huge amount of time, effort and research into each one and then spends just as long testing it, if not longer. They are well worth the changes that need to be made to the especs but the challenge remains on getting everyone on board, especially those who drive in DCC and don't care that an 0-4-0 can pull a 400 ton train up a 1 in 50 gradient unassisted at 60mph!

Cheers,

PLP

 

[EverTrainz]

have incorrect mass values as well as queue loads

ah that's a bummer, forgot about that. Opens up a new can of worms

 

[PortLineParker]

I don't see why the original authors wouldn't want to implement the changes - as I said, the amount of work Anthony has put into these specs is phenomenal and the driving experience is transformed, with your train smoothly gliding into stations to a gentle stop now possible with the emulation of vacuum brakes. The trouble will be reaching those authors who perhaps haven't been around for a while and those of assets that are now Packaged as these can't be modified locally. Assets not on the DLS will also need to be manually edited by the original author although personally I avoid non DLS assets like the plague.

Cheers,

PLP