[cesarbl]

I added a new token which allows the train brake controller to trigger dynamic braking on the whole train. This is useful for trains which have a dynamic-brake-only region on the train brake controller. This would be an example of how to configure the dynamic brake part:

Engine(
    ORTSTrainDynamicBlendingTable(
	0 (
            0 0 
            300km/h 0
        )
        0.3 (
            0 1 
            300km/h 1
        )
        0.9 (
            0 1 
            300km/h 1
        )
        1 (
            0 0 
            300km/h 0
        )
    )
)

In this example, from 0 to 30% of the train brake controller, dynamic brake ranges from 0 to 100%. Then, it stays at 100%, and is deactivated if the train brake controller is in emergency position. Different % of dynamic braking can be applied depending on speed, if required.

This feature is typically useful for MU trains. It is a separate feature from the "local" dynamic brake blending from modern locomotives, which replaces air brakes with dynamic brakes if available.

I also added the possibility of removing the dynamic brake controller lock at Setup position: dynamic brake lever can be moved to any position, but it will only start braking after dynamic braking has been engaged. I'd need some feedback on what should be the default value: lock in setup position (this was the standard behaviour up to now), or do not lock by default (this seems to be the most common case).

[superheatedsteam]

If it the lock at setup can be toggled then it doesn't really matter but my vote is to not lock by default.

[pschlik]

I would agree to not lock the dynamic brake handle by default. I think I mentioned a while back that I had yet to encounter a case where a locomotive has a mechanical lock on the dynamic brake handle in setup, and I still haven't heard of such a case.

The only 'typical' locks on the dynamic brake handle would be locking it in 'off' when the throttle is not idle (and conversely throttle is locked in 'idle' when the dynamic brake is anything other than 'off'), and locking the dynamic brake handle in 'off' when the reverser is in neutral (conversely the reverser is locked in the selected direction of travel when the dynamic brake is anything other than 'off'). OR only has some of these locks, so you can end up doing weird things that wouldn't work in real life.

[darwins]

cesarbl, on 14 September 2023 - 01:14 AM, said:

I added a new token which allows the train brake controller to trigger dynamic braking on the whole train. This is useful for trains which have a dynamic-brake-only region on the train brake controller. This would be an example of how to configure the dynamic brake part:

Engine(
	OrtsTrainDynamicBlendingTable (
    	0   0
    	0.3 1
    	0.9 1
    	1   0
	)
)

In this example, from 0 to 30% of the train brake controller, dynamic brake ranges from 0 to 100%. Then, it stays at 100%, and is deactivated if the train brake controller is in emergency position.

This feature is typically useful for MU trains. It is a separate feature from the "local" dynamic brake blending from modern locomotives, which replaces air brakes with dynamic brakes if available.

I also added the possibility of removing the dynamic brake controller lock at Setup position: dynamic brake lever can be moved to any position, but it will only start braking after dynamic braking has been engaged. I'd need some feedback on what should be the default value: lock in setup position (this was the standard behaviour up to now), or do not lock by default (this seems to be the most common case).

Thanks for that. It sounds like what I need to get this controller working:

Brake_Train ( 0 1 0.1 0.2
NumNotches ( 8
Notch ( 0	0 TrainBrakesControllerReleaseStart )  Comment ( Release / Running )
Notch ( 0.2  0 TrainBrakesControllerEPHoldStart )  Comment ( Hold EP )
Notch ( 0.3  0 TrainBrakesControllerEPHoldStart )  Comment ( Regeneration I )
Notch ( 0.4  0 TrainBrakesControllerEPFullServiceStart  )  Comment ( Regeneration II and EP )
Notch ( 0.5  0 TrainBrakesControllerEPFullServiceStart ) Comment ( Regeneration III and EP )
Notch ( 0.6  0 TrainBrakesControllerHoldStart ) Comment ( Lap Air )
Notch ( 0.8  0 TrainBrakesControllerFullServiceStart ) Comment ( Apply Air )
Notch ( 1.0  0 TrainBrakesControllerEmergencyStart ) Comment ( Emergency ) ) )

This case might be a bit more complicated than it at first seems though... https://i.imgur.com/OSHmYkp.jpg


https://i.imgur.com/6HgSAko.jpg

[Traindude]

Refresh my memory, do we already have dynamic brake force curve table parameters like we do with tractive force curves? It's worth mentioning that the dynamic braking curves are a little bit harder to obtain, since most locomotive data sheets and other literature don't specify them.

[Csantucci]

César,
what you are doing is very welcome in my country, as all modern locomotives have the train brake handle working like that: first position is dyn brake at 50%, second position is dyn brake at 100%, subsequent positions add train brake to dyn brake.

[ErickC]

While we are on the subject of dynamic braking, If I can make another suggestion - for diesels we really ought to have a parameter to define the engine RPM when dynamic brakes are engaged and at what amperage that throttle up takes place. I suggest the following:

ORTSDynamicBrakeEngineRPM
ORTSDynamicBrakeThrottleAmps

This is because the traction motors still require cooling when in dynamic braking, and on most locomotives the traction motor blowers are connected directly to engine RPM. First-generation locomotives immediately throttle up to about half throttle when dynamic braking is selected, but second-generation locomotives typically delay this until a high amperage is selected (in EMD parlance, this is "one-speed dynamic brakes" and "two-speed dynamic brakes" respectively). When the parameters are absent, the behaviour should be as default (no RPM change).

This behaviour can be seen here (one-speed dynamic brakes) and here (two-speed dynamic brakes - listen for the turbo whine between the 6:03 and 6:06 mark).

[Laci1959]

Traindude, on 14 September 2023 - 08:36 PM, said:

Refresh my memory, do we already have dynamic brake force curve table parameters like we do with tractive force curves? It's worth mentioning that the dynamic braking curves are a little bit harder to obtain, since most locomotive data sheets and other literature don't specify them.

Hello.

Yes, that's true, but the speed-dependent curve. I don't know why, because the curves of modern electric locomotives and EMUs are largely the same.
Perhaps the table you mentioned works with the value determined by the first table proportionally. Maybe?

Sincerely, Laci 1959

[Csantucci]

César,
only to be sure: also the player locomotive would work the same way? And if yes, what could be an example of the brake controller lines in the .eng file?

[cesarbl]

Yes, this affects the "Dynamic Brake" MU signal, and sets dynamic brake on all locomotives, including the player one. On the other hand, "local" blending, which was already implemented in OR, sets dynamic braking independently for each locomotive.

I just realized that I made a mistake in my first post, because that's not the correct syntax for OrtsTrainDynamicBlendingTable. The correct way to setup it is

ORTSTrainDynamicBlendingTable(
   <train brake position> (
     <speed> <dynamic brake>
   )
)

This allows different dynamic brake % at different speeds, and has a similar syntax to DynamicBrakeForceCurves

I'll provide an example .eng file when I get back to the computer, but basically the Train_Brake controller has to provide notches according to air behaviour (e.g. if a dynamic brake position holds air brake, then HoldStart should be used, if it releases air, then ReleaseStart is better choice)