Model Railroading > Walthers Number 8 Switch

I am having shorting problems on a Walthers number 8 switch. When a train takes the diverging route, it appears the metal wheel causes a intermittent short between the fixed rail and the movable rail on the frog. The short area is only a fraction of an inch, but a slowly moving train will cause a short. Usually, the momentum of the train will carry it by, but now with DCC and sound producing decoders, it is really a pain to get even a momentary short.

Any of you out there encountered this and what did you do about it?

A couple of things come to mind.

First, use an NMRA gauge to check the spacing on your engine's wheels. Many HO scale locos come from the factory with wheels spaced at the narrow end of the range, so to speak, and that can lead to back-to-back shorts in a hurry. Spread the wheels to their proper gauge and it may solve your problem.

Next, use the same gauge to check the track gauge through the switch, especially at the derailment point, of course. I've spent a fair amount of time tweaking the rails on Shinohara/Walthers and other brands of switches to bring them closer to standards. In regards to switch points, they sometimes need to be bent slightly to better match the opposite counterpart fixed rail.

Also, check for track defects at the short circuit point. If there's a tiny nick in the rail it can be all the wheels need to be tweaked sidways into a short circuit. Inspect the switch for level, as well, making sure all the rails are even.

Finally, if you DON'T have an NMRA standards gauge, haul yourself down to your hobby shop or check the NMRA web site and buy one posthaste. It's an indispensible tool for fine-tuning one of your model railroad's most important functional parts.

Jeff Johnston

(Note to those who don't have an NMRA gauge, and refuse to buy one, and have done fine all these years wirthout one, and who hate the NMRA ... please start a separate thread, OK? This one deals with the technical aspects of helping a guy with a switch problem. Thank you!)

Remember to turn off the DCC power before you set the NMRA guage onto the track, it's a little bit less exciting but worth it. The NMRA guage is very worthwhile for all sorts of confidence building.
There is also some discussion going around about reconfiguring the frogs or even the points for DCC. Quite a bit of work but it's out there. Some of the DCC users have their own discussion sites on Yahoo Groups.

Thanks for the pointers. I do have the NMRA gauge and it is amazing how many defects you can find, even wheel spacing on new equipment. I did check the gauge on the diverging route and found it to be a bit wide. Looks like it is time to prod and push those rails!

I had this problem and ended up modifying my turnouts. I did this by using the procedure described at:

http://www.wiringfordcc.com/switches.htm

Basicly you make each of the point rails the same polarity as the outside rails they are near. If they are the same polarity you can't have a short.

David

We have experienced this problem at our club even with a Walthers/Shinohara #6 turnout - particularly the new "DCC Compatible" turnouts - the point rails are curved and there is actually a "pinch point" i.e. narrowing about halfway between point and fulcrum. There are 2 styles of construction:

1. Point rails are hinges individually with a rail joiner and individually attached to the throwbar and isolated from each other. No problem with these as each point rail has the correct polarity. I think these are the older style.

2. The second style has points joined together with a metal strap rivetted to the throwbar - this is a big problem bec. both points are now the same polarity at any given position. We have not figured out how to solve this - basically the turnout needs to be reworked so that each point rail is electrically isolated from the other.

We have had no problem with 2-axle trucks but, with 3-axle trucks, the middle axle has side to side play and it seems to be this axle that causes the short.

Our solution is to select only the turnout style #1 above.

Walt Freedman
Sausalito, California

Walt, I have three pair of the Walthers/Shinohara turnouts of the type with the points tied together with the brass throw rods. Two pair (both curved) are at the ends of passing sidings and the third pair are on the connection between the outer loop and the inner loop. All tracks leading to the frog-side of the turnouts are double gapped. Everything is DCC with a Digitrax Super Chief system.

I apparently don't see the problem with this type of turnout that others have. Only disadvantage is that you can't spring thorugh the turnouts.

What am I missing?

DocJohn
Macon, GA

DocJohn - here is a link to the type of turnout we have problems with:

http://www.internettrains.com/948-802.html

Look closely and you will see that the points have a metal connection between them at the tips which means that they are always at the same polarity.

In the diverging position, we found that the play in the middle axle of a 3-axle truck brings a wheel into contact with the open point rail about half way along the movable length - which is at the same polarity as the closed point - and this causes a short with the stockrail.

It looks to us that the latest production actually has a narrower gap between stockrail and open point than earlier runs - we have lots of this style that are years old - and even with the old ones, now that we are aware of it, occasionally find the same problem.

The problem is really only apparent at really slow speeds - we were testing out a new installation after a major overall of a yard. Most of the time, momentum carries one through with only the slighest hesitation that I guess most people ascribed to dirty rail.

Walt

Walt, I have the old-style Shinoharas. Both points are at the same polarity. Have a pair of 6-and-1/2 curved, and a pair of 7 curved, and a pair of 10 regular. My passenger cars are Bachmann heavyweights in NYNH&H lettering which means they have 6-wheel trucks.

John