Braking and profiles

[Steppen]

Hello,
I'm a freshman here so let me first of all say hi!

There's one thing that puzzles me about automation.

I can set a lot of parameters for each loco in the loco database, but haven't found any place to enter braking data.

So when I'm running i.e. Demand Contact operations the braking is determined by the value in <Route editor>, <Route>, <Start/Brake/Dest>, <Braking, startV minus>.

Problem is that my locos have different running characteristics. I.e. one loco is running normally on 40 and has 15 as a good brake speed, while another runs on 95 and has 65 as a good brake speed (values from the train control).

So if I set the brake value to -5, it'll be noticable on the loco running at 40, but hardly at all for the loco running 95.

As far as I can understand that means that any profile I create to automate tours or DC operations will lack the possibility to brake my locos in an individual way, and that I'm left to simply stop them without a prior brake.

Is my assumption valid, or is there something I've missed? How are you all dealing with this?

(I'm running WDP 9.2 Int on a Thams controller using S-88 feedback contacts).


Sincerely,
Stein  

[Steppen]

I know, I know.. RTFM..  :cool:

The answer to my question above is: yes, it really is so that one need to tune one's locos in the loco database to make them "equal".

I was a bit surprised to learn that in version 7 the braking was given in percent, but that it was changed to absolute values in version 9 (see "seite 184" in the english manual). How comes?

So: Chapter 5.5 in the english handbook covers riding properties and dynamic behaviour of locos.

I guess that the part I'm struggeling to understand is:

• All speed settings are given in "steps", e.g. 1-127.
  
• The locomotive control gives the speed in persentage (of max), 1-100.
  
• And finally the breaking is given in voltage.  (+/- 70 (m)V)
   

Can somebody please explain how these values correspond?

Also; has someone an procedure example for how to test a loco and adjust properties to make the locos "equal" (so that they all will respond properly on the braking value given)?

Sincerely,
Stein.

     

[Adrian L]

Hello Stein,

I believe that the V is velocity and not voltage.. I also suggest that this section on page 183 contains an error:
"The program will interpret in operations value over 100% or lower than 0% automatically as 1000% and 0% respectively".
I guess that paragraph meant to say that if you use a number bigger than 100 in the box then it will automatically set the number to 100 (not 1000 as stated in the text). Therefore, I have always treated the number as percent in the route control.  

In short, section 8.7.3 says that the StatrtV +/- box is used to modify the speed of the loco when it starts the route and when it arrives at the first braking contact.. If you have 80 set as the start speed of your loco in the loco database, and apply the settings shown on page 182, then the start speed of the loco will be 60% and it will slow to 35% when it arrives at the braking contact.  Of course, when it arrives at the end contact it will be StartV -100 or 0 velocity.. Although it is hard to understand at first, it is a really logical way to deal with the problem of decoders with different speed steps..

In practice, the number does not matter.  You should set the  start speed, acceleration/deceleration and the braking contact values according to the behaviour that you want on the track.  In many instances this is to ensure that the loco and wagons halt in the correct place and not too far before or after the signal..  In some cases, where the running characteristics of locos are very different, it may be necessary to create two routes so that each loco uses a different route (see 8.9 loco type)..  Do you really want every loco to run exactly the same??  In real life each loco driver would slow to the posted speed at different rates.

To get the locos to run at the same speed for a throttle (decoder speed step) setting is fairly easy.  The problem is that this is not a linear relationship so that two locos that run at the same speed at 50% throttle will most likely run at a different speed at 25% throttle.    This is nothing to do with WDP, it is the decoder.

I use (mostly) Marklin, so I use tools like the 72600 speed sensor unit to check the speed at a particular throttle setting of WDP..  For finer work, I use the 78100 and 78111 combination with a link to WDP.

I hope this is of assistance.
 

[Steppen]

Hello Adrian,
Yes, your reply was most helpful and made a lot of sense.

I guess I was fooled by the statement "Possible values can (be) from +70 to -70 in steps of 5". From your explanation I now understand that it only means that a loco running with 100% as starting speed can't go below 30% in braking speed (which would be a very unrealistic speed change anyway  ).

And no, I certainly  don't want my locos to have the same driving characteristics - in my despair I just thought (althoug it was unlikely) that I might be forced to keep it that way. But that was all because I was mistaken about the "V", and interpreted it as Volt(not velocity) .

Thanks a lot for your clearification - can't wait to test this out on the layout!!