And yet another wiring problem - single crossover

[PIN DR]

I thought, after getting help to figure out the double crossover, that I was all set, but I guess not...

The last thing I am installing on my layout is a single lefthand crossover. It is a Shinohara left crossover. I have it going from my inner main line to an inside spur line running in two directions.

After installing it, I have a shorting problem. When it is set up to let trains run straight through each side everything is fine. But, as soon as EITHER end is thrown to allow the crossover, it shorts out. I know everything is wired correctly, so I'm thinking I must be dealing with an issue of the crossover not being isolated properly. The frogs have continuity from each end of the crossover, although there is an isolation joint in the middle of the crossover in between the frogs.

Do I need to cut a joint in each track on the outside of the frogs (toward the throw points)? Is the fact that the frogs are powered leading into the crossover my problem? I'm thinking maybe this crossover was made for DC operation and it can't figure out the DCC and the frogs need to be isolated from power from the ends.

Thoughts? If I can get this one solved, I promise, no more wiring issues!

Jeff

 

[PIN DR]

I couldn't stand it, I went back and sawed through the rails and isolated both frogs. The problem went away and now it works as it should. I'm going to run a couple wires from my Frog Juicer to those now isolated frogs, just to be sure locomotives get power all the way through the frogs, but the short is now gone and it looks like I'm all set...I hope.

Jeff

 

[fcwilt]

I don't know that specific unit but I can tell you this much about using Peco Electrofrog turnouts (with the frog powered via contacts on the switch machine).

As a result of the way the turnout is constructed the two rails after the frog on the UNSELECTED route are of the same polarity (they are connected together).

So I have to have gaps in the rails on the frog ends to prevent shorts.

I am using DCC and one "good result" is that if a loco tries to enter the turnout from the frog end via the unselected route, as soon as the loco crosses the gaps it creates a short which trips the electronic circuit breakers and stops the train.

 

[Iron Horseman]

After installing it, I have a shorting problem. When it is set up to let trains run straight through each side everything is fine. But, as soon as EITHER end is thrown to allow the crossover, it shorts out. I'm thinking I must be dealing with an issue of the crossover not being isolated properly.

Exactly. I know you already solved the problem but a insulated rail joiner or a gap just past the frog (away from the points) on the straight through side would have solved the issue. When the track is in a loop it is just like putting a feeder on the frog side of the turnout.

I'm thinking maybe this crossover was made for DC operation and it can't figure out the DCC and the frogs need to be isolated from power from the ends.

DC or DCC or AC or any sort of electrical power has this same problem. A short circuit is a short circuit. I dealt with this issue on my first layout in 1963(?), long before anyone knew what digital even meant.

 

[PIN DR]

That is very good information to keep in mind for down the road. I isolated on both sides of both frogs, which was overkill, but it works fine now anyway. If I deal with the issue again at some point, I will limit he modification to that one location.

Thanks!

Jeff

 

[PIN DR]

So, now I'm curious. If it doesn't make any difference, in this case, whether or not you are operating DC or DCC, why make the part this way? Why force you to figure out what doesn't work and make the needed fix, when they could have just made the part right in the first place? It isn't like a crossover is used in a dozen different configurations. Seems to me that it would short in any case, so why not put the isolation gap in in the first place?

Jeff

 

[Iron Horseman]

So, now I'm curious. If it doesn't make any difference, in this case, whether or not you are operating DC or DCC, why make the part this way? Why force you to figure out what doesn't work and make the needed fix, when they could have just made the part right in the first place? It isn't like a crossover is used in a dozen different configurations. Seems to me that it would short in any case, so why not put the isolation gap in in the first place?

The more gaps that are put in at the factory the more it costs to manufacture. But the big reason is that the more gaps that are put in at the factory the greater chances of equipment stalling. To make it bullet proof and prevent the stalling requires adding components like the "jucier" and more wiring. Some folks, like me, don't want to add all that extra stuff (and cost) and prefer just to put in a gap.

From a historical point of view, I think in the "old" DC days everyone had to understand how the wiring worked so this was just sort of a standard operational situation no one gave a second thought to. It has only become an issue with DCC because everyone just expects to "hook up two wires and go". I myself have often told people that that, forgetting that some will take that comment literally and not just in the proper context of controlling the trains.

 

[PIN DR]

Thanks, that puts it in perspective. Frankly, I would have been fine with having to learn about how to do the wiring in any number of ways, but they don't even bother to include any instructions with these parts, which would help. I have several books on wiring model railroads and none of them cover how to properly wire anything more complicated than a single turnout. Seems counter-productive for a company to make parts that are destined to fail in the hands of a large(?) percentage of those who purchase them. Just my thoughts.

Jeff