Atomic Systems

Either I'm late to this particular concept, or a bit slow, but it seems to me that dynamic brakes only work in the engine you're driving. Through some empirical testing with one of my EMUs, it would seem that even though the trailing driving car has driven bogies and dynamic brakes, they don't actually do anything.
So I guess the first question is - is that really the case?
And then the second question would be - anyone found a workaround? I tried scripting around it tonight but even once I was absolutely guaranteed that the Dynamic Brake in the rear engine was indeed being set, it still didn't seem to make any difference. (For what it's worth, it was being set without scripting but I needed to throw in some print-debugging to make sure.)

Doing a scenario on Marias Pass with 2 BNSF ES44 DC at the front and 2 pushers at the back, when using the dynamic brakes, on the back ones you could here the dynamic brake noise. Whether they were working or not I don't know.

I think the question we should ask ourselves, is in the USA diesels, where they run 2 or 3 units at the lead on a heavy consist, their dynamics work. Any of us here who has played any route where you require dynamics when going down a steep embankment would know that 3 units up front with dynamics applied can slow almost any weight train, without wheel slipping... So, that either means the lead unit's dynamics are set extremely high, or all the units in the consist are doing the same power/dynamic operations...

Virtual Railroads also managed to get the DVT correct, with correct power/dynamic operation for rear locomotives, so there must be a way forward to get all the driven vehicles in the consist to behave exactly as the lead unit, whether it's powered or not... The class 390 should also behave that way, as I believe there is more than 1 driven vehicle in the set... That train uses dynamics as the main braking source, and then switches over to air at low speed... So I think there is a way around the problem as mentioned about, as it seems to have been done before...

The latest DB BR423 have 2 powered cars in the set, and those dynamics and power work too well... So case in point, it should be possible, but the exact method is not known to me...

how do you know if dynamic brakes work well on those EMU-s and not on the locomotives?
By the way i see signs of HRQ Tauruses have working dynamic brakes in MU mode too, as the power converter sounds are attached to the ammeters, and i can hear that sound on dynamic braking. Also if one helper loco is at the other end of the train, and i use loco brake to bunch the consist, then use dynamic brake, the consist gets streched, which means the helper loco is braking the end of the train.
I think the game engine knows does this by default since an update 1-2 years ago, if not, try setting "Apply on Consist" to true on DynamicBrake control value.

chrisell wrote:Through some empirical testing with one of my EMUs, it would seem that even though the trailing driving car has driven bogies and dynamic brakes, they don't actually do anything.
So I guess the first question is - is that really the case?

How do you know the other EMU vehicles in a set are not braking when you apply the Dynamic Brake?
If only the lead vehicle in an 8 car set braked then -
1, the brakes would not be good enough to stop
and 2, they would 'bounce off' the lead coach on stopping.

Peter

749006 wrote:

chrisell wrote:Through some empirical testing with one of my EMUs, it would seem that even though the trailing driving car has driven bogies and dynamic brakes, they don't actually do anything.
So I guess the first question is - is that really the case?

How do you know the other EMU vehicles in a set are not braking when you apply the Dynamic Brake?
If only the lead vehicle in an 8 car set braked then -
1, the brakes would not be good enough to stop
and 2, they would 'bounce off' the lead coach on stopping.

Peter

A Normal EMU in (this case) is two driving trailers with two coaches in between. I put a "start here" marker in my test route and then get the train up to 120km/h. At the start point, I apply 50% dynamic brake and let the train slow to a complete stop (I have a blending script that transitions from dynamic to air brakes at low speeds), then put a "finished here" marker in the route.
I then re-jigged the consist by taking the rear driving trailer away and adding a third wagon of equal weight in its place and ran the test again. I stopped about in the same place, give or take 5m or so. If the rear driving trailer, when attached, had had working dynamic brakes, the stopping distance with it attached would be shorter.
Similarly, if I put two 4-wagon EMUs together in the same consist, despite the doubling in weight, I'd expect the braking distances to be similar (though not exactly the same). In the game, when you do this, the braking distance more than doubles. Sort of what you'd expect if you doubled the mass of the train but added no more braking capacity.
I actually think there's a deeper issue here - I've had to script all sorts of things to get around game bugs for EMUs. For example the accelerometer / traction readings don't pass up and down the consist correctly when you have back-to-back EMUs. One driving trailer will show positive acceleration, the other negative (even when it's the end that is moving forwards).
I wonder if the dynamic braking thing is another symptom of this? I wonder if it simply doesn't understand what to do because one of the engines is facing the other way?

Theoretically a Driving Trailer, or any Trailer, should not have dynamic brakes.
By it's name the Dynamic Brakes should only apply to powered vehicles.
Swapping the rear Driving Trailer with a coach of equal weight and then just applying the electric brakes should have you stopping at the same spot.

A test might be for one 3 car EMU to stop on Dynamic Brakes only - then repeat the test with a 6 car EMU - they should both stop at the same point.

Peter

When they brought push pull operation on the WCML they disabled the rheostatic braking when propelling due to shocks it created through the train.

The smell of brake pads on the up trains at Oxenholme that had descended Grayrigg was quite something!

B

749006 wrote:Theoretically a Driving Trailer, or any Trailer, should not have dynamic brakes.
By it's name the Dynamic Brakes should only apply to powered vehicles.
Swapping the rear Driving Trailer with a coach of equal weight and then just applying the electric brakes should have you stopping at the same spot.

A test might be for one 3 car EMU to stop on Dynamic Brakes only - then repeat the test with a 6 car EMU - they should both stop at the same point.

Peter

That's my bad - I'm mixing metaphors here. When I say "driving trailer" it's actually a power trailer at each end of the EMU. So both ends have electric powered bogies, ie both should be using the dynamic brake.

That being said, I had a total "d'oh!" moment this morning. I realised that because the primary brake in the engine cars is dynamic, and because I only blend in air brakes below a certain speed, the passenger wagons contribute nothing to the consist's braking ability at high speed. I need do alter my passenger wagon scripts to intercept a message from my engine cars and apply their air brakes at the same rate the engine cars use their dynamic brakes. Which is pretty much what happens in the real train but I totally spaced it. And have continued to not figure it out for 6 incremental releases already

bdy26 wrote:When they brought push pull operation on the WCML they disabled the rheostatic braking when propelling due to shocks it created through the train.

The smell of brake pads on the up trains at Oxenholme that had descended Grayrigg was quite something!

B

Totally Incorrect.

I have done many journeys with Classes 86, 87 & 90 in Push Mode and the Rheostatic brakes worked every time the driver applied the train brakes.
The smell of brake pads at Oxenholme and other locations would be the same after hard braking.

I'm sure if you go for a ride behind the same class 90's in the same Mk3 coaches between London & Norwich you will still get the same smell.
Unless the brake pads have been changed for one's that don't smell.

Peter

chrisell wrote:
That's my bad - I'm mixing metaphors here. When I say "driving trailer" it's actually a power trailer at each end of the EMU. So both ends have electric powered bogies, ie both should be using the dynamic brake.

I think a 'power trailer' is also a bit confusing. I don't think it can be both powered and a powerless trailer.

749006 wrote:

chrisell wrote:
That's my bad - I'm mixing metaphors here. When I say "driving trailer" it's actually a power trailer at each end of the EMU. So both ends have electric powered bogies, ie both should be using the dynamic brake.

I think a 'power trailer' is also a bit confusing. I don't think it can be both powered and a powerless trailer.

Engine that happens to look like a passenger car?

chrisell wrote:

749006 wrote:

chrisell wrote:
That's my bad - I'm mixing metaphors here. When I say "driving trailer" it's actually a power trailer at each end of the EMU. So both ends have electric powered bogies, ie both should be using the dynamic brake.

I think a 'power trailer' is also a bit confusing. I don't think it can be both powered and a powerless trailer.

Engine that happens to look like a passenger car?

In UK terms
Motor Coach with Cab is Driving Motor Second (or First)
Motor Coach without Cab is Motor Second

The only thing I will add is did you make sure the brake was "applied to train"?

749006 wrote:

bdy26 wrote:When they brought push pull operation on the WCML they disabled the rheostatic braking when propelling due to shocks it created through the train.

The smell of brake pads on the up trains at Oxenholme that had descended Grayrigg was quite something!

B

Totally Incorrect.

I have done many journeys with Classes 86, 87 & 90 in Push Mode and the Rheostatic brakes worked every time the driver applied the train brakes.
The smell of brake pads at Oxenholme and other locations would be the same after hard braking.

I'm sure if you go for a ride behind the same class 90's in the same Mk3 coaches between London & Norwich you will still get the same smell.
Unless the brake pads have been changed for one's that don't smell.

Peter

They did change the brake pad compound to reduce the smell.

I'm not making it up, it was written up in RM in 1990/1991.

B