Shorting on UCS - help needed

[Anonymous]

Hopefully, a simple question from a relative newbie.

I'm runing a simple TMCC layout on O27 tubular track with one uncoupling section and one uncoupling/operating section. When my tender or caboose (lighted) go over the uncoupling section, there is a momentary short when the pickup rollers are directly over (touching?) the core of the magnet. If I manage to stop the train at exactly the right spot, or go veeeery slowly over the section, it will actually go "dead" due to the short. At higher speed, the lights blink and I can see sparks under these cars. None of this happens when running the engine over the section, nor does it happen when passing the tender or caboose over the uncoupling/operating section.

I'm guessing the problem is that the pickup rollers are actually contacing the magnet and causing the short. The space aroung the magnet looks to be wide enoughy to allow the caboose and tender rollers to drop down and make contact.. The rollers on the engine are wider, so that would explain why I am not having a problem with it.

Does that explanation make sense? If so is there any easy fix? Maybe fill in a little with epoxy around the magnet?

If my explanation is off-base, can any offer another explanation/fix?

Thanks in advance for your help.

Dave

[Anonymous]

[#oops] Nevermind.

It dawned on me that there are a lot of things that stop electricity without affecting magnetism much, so I covered the entire red center section of the uncoupling track with black electrical tape. Everyting is now working fine. I even like the look better - it makes the section stand out a little less.

Of course someday the tape will wear out or come off, and I'll have to think of a more permenant fix, but that's what I said when I duct taped the deflector back on my lawnmower four years ago.

Cheers

[lionelsoni]

Modern uncoupling tracks have a steel strap under the magnet, with its ends turned up and stuffed into the bottoms of the outside rails. (This is to extend the magnetic circuit to the car's wheels and truck.) There probably should be an insulator between the magnet and the strap. I don't have one here; but I would guess that you can pull the strap away from the magnet enough to slip in a piece of heavy paper or light cardboard.

You may have noticed that the uncoupling magnet extends below the bottoms of the ties. I have found it desirable to shim the ties closest to the magnet and ramp the adjacent track up as necessary. In one case where that wasn't convenient, I gouged a shallow pit in the table for the magnet.

P.S. I looked at a couple of examples. The insulator is a piece of cellophane tape stuck to the strap. Yours may be missing or, more likely, torn or punched through. It is not difficult to remove the strap if you want, put on another piece of tape, and press it back into the rails.

[brianel027]

Dave, you don't mention what make of caboose and tender it is that is giving you the problem. On the newer types of cars, both Lionel and K-Line have used a shorter small roller pickup. K-Line in recent years has gone to a bigger and longer roller pickup assembly. I have some similar problems as you are having with these newer types of roller pickups. I haven't had too much trouble with the older type of pickup assembly, other than the fact the wires the companies use are thin and they don't use much solder to attach the wires: I frequently have to resolder or replace wires. But once I make the repair, then it stays fixed.

I switch pick up assemblies around and use the newer type of roller pickup with plastic trucks and use the slightly older type with the diecast metal trucks.

Problems with pickups shorting out on switches and operating tracks have been had by others too. There is so much variety these days on this kind of stuff... not only is K-Line using a longer assembly to hold the roller pickup, but the actual roller is also wider than previously - which can also cause problems.

I'm sure what is happening is that when your cars with the roller pickups go over the UC track, because there is a light rise on the UC center rail (same goes for regular uncoupling tracks and switches) the roller pickup makes contact with the ground causing it to short.

I will also say from experience that the Lionel 027 Uncoupling track is far better than the K-Line one. It doesn't stick up as much and does a better job uncoupling. On the other hand, the new K-Line 027 switches appear to be a big improvement over the Lionel MPC era ones that have been made for the past 35 years. Walt Rapp and Spankybird* use the new K-Line switches and really like them.

[Anonymous]

The caboose and tender are indeed newer Lionel - they're from the SP Overnight set. The problem was that the rollers were narrow enough to let them dip down into the beveled hole around the magnet and make contact. No ideal why the bevel is even there. It doesn't seem to serve any particular operational purpose. I guess maybe its for some assembly reason.

I do use mostly the K-line switches (I've stil got two Lionels to replace), and I do see some sparking when the cars go over them, but it doesn't cause any noticeable problems, so I decided that its in the "aint broke" category.

Or should I be more concerned?