Problem with Peco Crossings + DCC

[Peter749]

I'm in the process of building my first big layout but I have a problem with a set of points/crossings and DCC

I have a set of double crossings and so far everything has been running on test using DC Control

The layout has been build with DCC Bus fees around the layout but fed with DC

 

Today I swapped to DCC Control and I tried the Bachmann Blue Pullman and as it crossed this set of crossing I get a Short - reset, move about half a coach and another short - repeat about three times until the train was clear

 

I'm using Peco Streamline OO Gauge Insulfrog Points and Crossings with a number of insulated fishplates to split the feeds

Picture attached - Layout is still work in progress

 

I have no had any problems on DC but just today with the Pullman on DCC

 

Does anyone know what the problem might be and how to solve it?

 

Thanks

 

Peter

 

[RFS]

Yes I'm afraid this can be a problem with these Insulfrog crossings. The issue is that there is very narrow separation at the vee rails (presumably for realism) and any metal wheel with a wide tread, or an inaccurate back-to-back, can touch both vee rails as it traverses the crossing causing a momentary short. 

 

It's still a problem on DC, but the short is "tolerated". However, DCC is much more sensitive, hence you're seeing a problem. Try operating under DC in the dark and you may well see small sparks as the vehicles cross.

 

I gave up on my crossings and replaced them with Electrofrog ones.

[Peter749]

Thanks Robert,

 

I'm not having any problems with the Pullman on the other points where the fiddle yard is and I have an Insulated Fishplate after each Frog

 

Not sure if it could be either the diamond crossings or the back to back wheel dimension on the Pullman

Plus the Pullman pick up on a lot of wheels and feeds thru the train.

 

I will keep testing and decide if I'm going to replace the points or do something else - depends if other vehicles have a problem

 

Peter

[FoxUnpopuli]

Couple of coats of clear (nail) varnish over the vees? 

 

https://www.rmweb.co.uk/community/index.php?/topic/38137-peco-crossing-shorting-issues/

 

 

[John ks]

On 05/09/2020 at 00:30, FoxUnpopuli said:

Couple of coats of clear (nail) varnish over the vees? 

 

https://www.rmweb.co.uk/community/index.php?/topic/38137-peco-crossing-shorting-issues/

 

 

 

 

This problem has been raised before & several people (including me) have come up with the nail polish method

Disadvantages 

it increases the length of the dead section at the V 

It will ware off eventually

Advantages

Cheap 

Quick

Easy

What FoxUnpopuli said but with pictures

The red part is the minimum area needed to be covered with nail polish 

John

 

 

[FoxUnpopuli]

A picture is worth a thousand words.  However, since we're on DCC here, we can discuss stay alive capacitors for the first problem.  I don't know what brand of decoder you favour, but many if not most decoders can support a capacitor. Smoother running in general vs extra expense and some packaging and wiring challenges,  However, since we're straying off-topic...

 

It occured to me that even though it's an insulfrog crossng we're talking about, and you mentioned you were using insulated rail joiners - a bit of cunning with some electrical switches hooked up to the feeding turnouts could allow you to throw the polarity of the offending rails.  Worth investigating?

[DCB]

I  am afraid it will need a major rethink.  The Peco short crossing really has to be treated as being Live Frog when used with super sensitive DCC controllers for the reasons shown in the drawings above.  Best solution is probably  to actually bridge  the wiring at the frogs and use insulated joiners and frog juicers.   Which means taking it all apart.... 

[RFS]

You might want to re-think the whole crossing. This configuration would give the same connectivity, although only one train can traverse the crossover simultaneously instead of two. Although there are now 12 turnouts rather than 8, there's only one crossing instead of 8. This could be made Electrofrog to eliminate the issue. 

 

 

Bear in mind also that Insulfrog points can have the same problem. You can fit insulated rail joiners on the vee rails to overcome this, but then you are reliant on good blade connectivity instead. This configuration really needs Electrofrog turnouts for best reliability with DCC.

Edited September 6, 2020 by RFS

[Peter749]

I have two DCC Systems - The Bachmann Dynamis and a Lenz LH90

Purchased the Lenz LH90 quite a few years back and a few years back purchased the Bachmann

 

Both have their good and bad points - The Bachmann is easier to Program and the Lenz is easier when running.

I found that I had tried using the Bachmann system to test the newly programmed Blue Pullman when I had the problem

 

Further running with the Lenz system does not cause the fault - maybe the Bachmann is too sensitive?

 

Peter

[RFS]

DCC systems do differ in their level of sensitivity. When I experienced this problem it was with a  Lenz LZV100 system. I've since upgraded to the LZV200 system, with the LZV100 now managing turnouts and accessories. I believe the Bachmann Dynamis is quite sensitive.

 

I found several locos exhibiting the problem, especially when driven over the crossings slowly, and these were recent productions (Bachmann 9F, Hornby T9 etc.).