DCC short when using Peco insulfrog switches

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I am new to MR and I am building a simple double track dog bone layout. I am using EasyDCC by CVP Products and Peco Insulfrog switches. The layout(under construction) starts out as a single track then braches off to a double track. At the switch where the track becomes two, when running a Bachmann 2-8-0 with all wheel pickup crosses the frog a short occurs(The same happens when I run a New Bachmann K4). When I run an Atlas Classic GP7 the short does not occur. I have isolated the switch with isulated rail joiners and at no point do either of the rails cross one another. The second track for the main line is still not complete so it ends about 25 feet away, this will eventually switch back onto the single main line. I have gone as far as to replace the switch with another Peco and still have the same problem. this is getting pretty frustrating since the layout is in its infantcy and I am having these problems. If there is anyone with any ideas please send them my way.



-- Peter Lokuta (plokuta@sprynet.com), October 05, 1999


The Bachmann wheel flanges on steamers are over-sized. As it passes over the switch the bottom and/or back side of the flanges touch the opposite wing rail causing the short circuit between rails of opposite polarity. You need to either make your track switches 'DCC Friendly' (see other message threads & web-sites), or cut down the wheel flanges, or use a different brand of switches with more flange way room.

-- Don Vollrath (dvollrath@magnetek.com), October 06, 1999.


Look closely at the turnout.

1. Note that the stock rails (not the closure rails) entering the frog, come very close together. 2. PECO's flangeways are excessively wide. This allows a wheelset to drift too far towards the frog - especially in the diverging route.

1. and 2., combined, allow can any metal wheel to create a momentary short. The wider wheels, on some locos, make the problem worse. This short will trip a fast electronic circuit breaker and surely pits the wheels.

I do not know how to easily correct the problem. You could grind away some rail with a Dremel cut-off wheel but that's a lot of work, risks damage to the turnout, and may create a bump.

Since you probably are not using circuit breakers, this may not be the problem. Nevertheless, everyone should be aware of this issue and it is one of the reasons we don't use HO scale PECO turnouts. Do note that the PECO code 55, N scale turnouts, are great but that doesn't help HO scale folks.

Ross Allen, owner, RAILSERVE

-- Ross Allen (ros310@hotmail.com), November 07, 1999.

I believe answer 2 describes your problem correctly. I have solved it by taking a needle file that has two flats that meet at about 150 degrees or so and filing the railheads at the point of the frog so that the two railheads slope towards each other. This prevents the wheel treads from bridging the two rails at the point of the frog causing a short. I have noticed that the PECO Insulfrog switches show some variation in the thickness of the insulation at the point of the frog, with the short problem only being present when the plastic insulation piece between the rails is thin.

Dale Gloer

-- Dale Gloer (dgloer@ca.ibm.com), November 08, 1999.

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