Afb Question

Question for anyone familiar with the operation of real German trains.
Is AFB ever used to slow down for station stops?
Or is that all done with the train brake?

For example, I like to come into a station at about 50 kph. If I used the AFB to slow to 50, then the train brake to stop, is that a realistic move?

In the game it technically works but I’m a fan of realism and I like the context from the real world.

 

You would not use AFB for stopping at a station, you shouldn’t even use it to reduce speed for a lower speed limit. Consider it more as a system that stops you from going over the speed limit rather than an „automatic train speed control system“.

 

Cramnor makes sense, thanks.
And just for further context, what negative effects would it have on the train or the passengers if you used it to slow down?

 

Extremely hard and sudden braking. Not fun for either passengers nor couplings.

 

I’m not 100 percent sure if that regards every train, but for example with the Br101 the AFB CAN be used to slow down, but due to the hard and direct braking of the AFB train drivers don’t use it to let the train drive more smoothly

 

Don't qoute me on this, but I believe that AFB would apply the brakes too fast, I think that ideally you want to apply the brakes notch after notch with a ~2s interval between each movement

 

Exactly. Lowering the AFB lever below your current speed essentially makes the system think it’s speeding horribly. That’ll most likely result in an immediate full service application.

 

You can use it. Remember that some engines are natively driven under AFB mode indeed (br143, br155, etc). Braking effort can be adjusted in some of them using the cab controls dedicated to that.

Cheers

 

BR 155 does not have afb tho

 

Ah yes... It's the 112 what I meant. The one used in Hamburg route.

Cheers

 

Wait, are you saying you are meant to use the speed control handle on the 143 and 112 to brake? I've been cutting off the power and using the brake handle, the same as the other locos so I get a blend of air and electric brake.

 

Some nitpicking to be done here. Neither the 143 nor the 112 use AFB. They use a much more rudimentary system compared to AFB.

How you’re doing it right now is how it’s done in real life as far as I’m aware. Same reasons as above.

 

Yes, it's totally fine for speed reduction, again I might be wrong, but:

1. Braking/Tractive effort to 0 until tap changer shows 0
2. Set a lower speed than what you want to achieve, generally 10km/h below target speed is good.
3. Modulate Braking/Tractive effort to achieve the braking you want.
4. Once you are at target speed or slightly below set Braking/Tractive effort to 0
5. Wait until tap changes is at 0
6. Set selected speed (likely speed limit).
7. Increase slightly braking/tractive effort and let AFB hold your speed.

That's generally what I do for reducing speed in the BR143

 

That is a (somewhat) prototypical procedure. The only difference in the official way of doing this (according to an old DR training film available on YouTube) is to set the speed selector to on instead of 10 km/h lower. In other words:

1. Traction force selector to zero
2. Speed selctor down to on
3. Use traction force selector to manually engage the electric brake (50% on the selector equals 100% of the electric brakes)
4. Slow down to target speed
5. Traction force selector to zero
6. Speed selector to the new speed
7. Traction force selector back to desired level

As I said, basically what you’re doing, just with a slightly different setup for the speed selector.

 

I see. I use -10km/h because the way the speed set is programmed means you have finer control the closer you are to Vsoll, and it helps especially when you don't actually have the handle but trying to emulate its use via key presses. So in terms of realism it's a sacrifice I'm willing to make

I'd love if the added support for analogue input, whether it is a HOTAS or a custom controller or even using the triggers on the joypad.

 

I mean, who’s to say that your way of doing it isn’t done in real life as well by some? What is taught in an old training video and what is done 40 years later in real life might differ a whole lot

 

Yes, you can still use speed control to brake. There´s nothing wrong with it. The locomotive will use the electric brake to adjust to the new speed. It´s that´s not enough to reach the new speed in time (e.g: to reduce speed after a yellow aspect under PZB) then you can use the pneumatic one manually.

In Spain for instance the high speed trains have ERTMS + AFB. The AFB will just follow the ERTMS braking curve to the stop location automatically. In that case this is possible cause the train bus sends the current ERTMS permitted speed to AFB everytime but from a formal operational perspective there´s no difference to set a lower AFB speed (or cruise speed limit if train has a different system) manually to perform a stop. It´s just an assisted way of driving at the end of the day.

Cheers

 

RE: the BR112 (and AFAIK the BR143 too)

they are missing one pretty important button in the sim that they have in real life (and in the virtual railroads versions of this train on TS20xx)

the 'Freier Auslauf' button,
the 'free rundown' button in english,

it's also missing the brake / power lever interlock because of this,


in reality you'd press the Freier Auslauf button well before you need to use the brakes, as this button makes the tap changer notch back to zero, something that can take ~30 seconds if you are in the highest notch.

Only when the notch display is showing 00 can you use the brakes,
similarly you can not move the power/speed lever back farther than the 20kmh setting without pressing the Freier Auslauf button,


in TSW you can have the BR112 doing max speed, in the top notch, and apply the brakes without issue.

In reality doing this would try to feed the dynamic braking current back into the motors that are pulling power from the overhead line still, you'd get a bit of a bang as the main breaker opens and tries to break hundreds of amps... likely damaging the contacts in the process.

i do wonder why DTG did not model the Freier Auslauf button in the BR112, is it because it makes the train too hard to drive for some people? (if so, make it optional... like TS20xx has simple and advanced driving controls)
or is it because they ran out of buttons on the consoles controllers to map the Freier Auslauf button to?

My favourite train to drive is the BR112, but it's so annoying it's missing such an important feature like this.

 

It isn’t modelled because the beta team member advising DTG on the 143 wasn’t aware of it until shortly before release (of the DRA 143 that is). However, using it is easily enough simulated by putting the traction force selector to zero.

 

dang,

i really wonder why they don't update the trains with these things as they discover them,
i'd even be willing to pay a small 'update' fee to add in more of the real driving features.

I'd even support 2 separate loco's, a basic version that you can just get in and press a few buttons and be driving it,

and a full feature, you gotta learn to drive this or you'll get nowhere version with all levers, switches and displays working, like the virtual railroads Expert Line loco's in TS20xx.. or TSC as it's now called.