Stopping Distance and Braking Contact

[SPIKE1320]

Hello,
Being new to Win-Digipet I'd like to understand how accurate the stopping distances are? Will every loco stop at exactly the same point, or is there some variance?

And is it essential for the "STOP" contact to be short in length and the "BRAKING" contact to be relatively long, or can they be any length?

Thanks,
IAN

[michael1957]

Hello Ian,
you can adjust the stopping points in WDP up to 1 cm exactly. It is very important, however, that the locomotives are precisely measured and that the braking distances are adjusted as accurately and identically as possible (decoder settings and brake corrections). Having done this you will be able to determine the stopping points very precisely. The length of the contact path for braking and stopping depends on the scale of your system and the speeds you want to drive, especially before the braking points. If you reach the braking path with 160 km / h of course the braking distance will be longer than if you only get there with 80 km / h. For H0 I have installed brake contacts of about 50-60 cm, the stop contacts are as long as the longest locomotive of my system is (in my case about 35 cm). In H0e (here I drive my locos with a maximum of 50 km / h) the brake contacts are usually 26 cm and the stop contact is about 15 cm long.
Much success, beest regards and greetings from Austria! Michael

[SPIKE1320]

Hello Michael,
Thanks very much! My system is HO.
I have measured them precisely. And I have all my loco's set to prototypical speeds using a Fleischmann speed wagon. There is a big difference from my slowest to my fastest eg: I have a class 81 with max speed of 45kmph and a class 103 with max speed of 200kmph.

If the braking distances should be similar, doesn't this present a problem. what is your suggestion in this case?

Thanks, I appreciate your time!
Regards from sunny Australia1
Ian

[ebarra]

Hi Spike,
Just to add some,comments to Michael answers I would like to add.
I can hardly get 1 cm accuracy even with locks with esu decoders (which seems to be the more consistant)
Nevertheless, If stopping a train to a given position using ITDN is quite accurate ( but not with 1cm repeatability) once calibration and breaking of each loco is fine tuned, the stop distance using distance in profiles has no coherence at all with the distance requested while it should be as accurate than with the ITDN. It a shame as I really need those in shunting mode.
This remains unclear and I never got any reply on this.
If Michael can describe how he can get such accuracy on the stop position , I would love to learn how he manage to do it. I am working on this for at least two years on this topic.

Regards.
Eric

[michael1957]

Hello,
I will try to explain and describe tomorrow evening if I can come back form my job at time. Have a nice evening! Regards, Michael

[Adrian L]

I find that ITDN delivers a VERY accurate stopping distance regardless of the speed of the loco, BUT it does seem to be influenced by the input voltage of the transformer.  In OZ we can have 260V in the morning and 230V in the middle of the day..  This seems to, at least on my Marklin-based layout, affect the voltage at the track which makes a very slight difference to the stopping position. However, all the locos seem to stop with the same variance - I suspect that this is where the 1cm is coming from..

To get the best result, you need to use the 15 calibration points, and use longer contact areas as described in the manual with very clean track and very clean loco wheels.  My experience with rolling road style calibration (e.g. Speed cat) is that it is inaccurate and suffers from wheel slip during the testing.

On a small layout, stopping a 160Km/hr loco will be accurate, but will not look very prototypical.   As my layout is fairly small these days, I only run my locos, including the Thalys, at 35 to 50km/hr..  After all, the Thalys does not roar into the Gare du Nord at 300Km/Hr.

[SPIKE1320]

Hello Guys,
Thanks for all the help. For sure this is mostly my lack of experience with this program.

I have three rather long contacts in the route 180cm - 180cm - 160cm. In order of entry the speed decreases, from driving speed 60kmph, - 1st contact 45kmph, - 2nd contact 30kmph so in effect all trains drive into the stop ITND (3rd contact) at 30kmph, and this looks realistic. (If a loco can't reach 60kmph it just keeps driving at it's max speed to the second contact when it slows to 30kmph)

I'm really interested to hear what you have to say Michael, as I think this is my biggest problem = the ITND where it stops is too long?

One thing I've noticed, the loco's with ESU decoders seem more accurate, if it looks like they will stop short, they keep crawling along until they stop close to the stopping point, but not 1cm. On the other hand, loco's with Zimo, Doehler & Haass etc decoders, just do their own thing and stop seemingly everywhere. I've tried setting CV#4 @ 1 but the loco decelerates slow quickly all passengers and the driver would be thrown out the front of the train. So in riding properties I set the accelerate and decelerate sliders to slow, but again I'm back where I started and the loco's stop wherever.

On the other side, this is also a problem at the turntable, where driving speeds are slow?

So I'm reading all this with interest, and thanks for all the input. I'm using the 2015 manual as there is no English 2018 available yet. There is a new section in the 2018 version = 6.2.6 regards fast and slow trains, maybe this will help?

Thanks,
Regards from Australia,
IAN
P.S. I find the Fleischmann speed car very accurate, it matches the speed that Windipet displays within 1kmph!

[michael1957]

Hello,
I'm sorry, but my detailed contribution with the explanations of my settings and with a youtube link from this afternoon is unfortunately no longer findable. I don´t know what happened! I will try to give some explainations later in this night or tomorrow.

Here the youtbe-Link: https://www.youtube.com/watch?v=uf0R6l0NDTM

Regards from Austria, Michael

[michael1957]

Hello,
now I will try to repeat my explainations which where lost after sending in this afternoon.

The most important factors for braking and stopping the trains precisely are, on the one hand, precisely adjusted locomotive decoders (maximum speed, medium speed, braking and acceleration values) and precisely measured locomotives (15-point measurement or better method). The second major factor is the length and distribution of the ITND. Longer ITND are favorable, but they should be divided into several feedback areas. This allows WDP to re-adjust the brakes after each feedback contact. Furthermore, it is important that your trains can enter the holding section at the same speed if possible (the largest part of the braking distance must therefore already be before the stop aerea) and then stop as exactly as possible at the same point. Also important - as already been written - the cleanliness of tracks and wheels of the locomotives. Best regards from Austria! Michael

[SPIKE1320]

Hello Miichael,
Thanks very much for the explanation. After much experimentation I think I understand my problem. My decoder speed curve settings are incorrect and I have not calibrated the loco's to match. At the moment, I have the loco's stopping within 10cm's so I think with the correct decoder adjustments I will have more success.

Thanks everyone for your time and input, it has helped me to understand more about the correct setup!

Regards,
IAN