Hi all,

I have an old Marklin E10, #3039, that I converted to digital. While it's not finely detailed, it's heavy and it ran just great, and the Loksound decoder has wonderful train sounds. Plus, the weight of the locomotive was helpful in pulling trains up the ramps in my new layout. When I started the new layout with hi-speed switches (Marklin 24711, 24712), short-circuits started happening, and while I first suspected the shoe, I was able to determine that it was actually the older wheels, which have a longer flange than newer wheels. I took the shoe off and simply pushed the loco through the switches and still got short-circuits. An older thread here helped me out on that, which showed that the middle rail gets very close to the outer rails at a certain point on the hi-speed switch, and older wheels are big enough to cause the short-circuit. The solution recommended was to get new wheels or grind down the old ones, which I'd rather not do. I have been searching and can't find any wheels where it's clear there will be a one-to-one replacement. So, I ask - does anyone here have any advice?

Thank you, John

PS - unfortunately, the last short-circuit fried the decoder. But, since I've already replaced the motor and so forth, I think a new decoder and new wheels will still be a lot less than a new locomotive. Perhaps I'm just feeling sentimental about it :-).

There is or maybe was a liquid insulation which could be painted on to the required item , very effective , could also be used on screwdrivers & other tools for the same purpose . My wife was working with the opposition to Selleys at the time back in the mid 80's before they were brought out by Selleys . The liquid insulation was still being produced for a few more years then disappeared off the shelves for a few years , I have seen it a few years ago in one of our Big Box shops but I have no current info on the product . Maybe a search of the bigger electrical & tool shops that supply everything may turn up something similar .



Cheers Tom in Oz .

These are great suggestions!

I also found one that involved putting the smallest heat-shrink wire insulation around each nub, heating it to shrink it, then cutting it off with a razor blade at the top of the nub. Since I already have some heat-shrink, I am going to try that first. If that works, Alan, your suggestion of using wire insulation is probably the better longer-term solution - the insulation is likely more durable. If nothing works, I'll try the paint-on insulation. I'll report back and let you know how it works.

Thank you, John

Hi John
I know of that problem.

May I suggest you first measure the spacing between flanges?

The original spec is 13.8 mm for Märklin.
Just happens to be very critical for 2471x switches, and one of the reasons we don't have a "sleek" double slip yet in the C-track assortment.
On the other hand, C-track is a little more tolerant if you go a bit wider on the flange spacing..
Taking just a loose axle from a coach , and it's easy to see where the short takes place

Simplest (and 100% effective) solution is indeed to insert little 3mm pieces of shrink tubing on the 8 raised pukos where the shorts will tend to occur.
(I pre-cut them and just touch them briefly with the tip of my soldering iron)

Another remedy is to carefully bend the pukos towards the center, away from the rail.

Both suggestions way easier than changing wheels or adjusting spacing.

Hope this helps

Cheers
Jacques

That did it! Used heat-shrink insulation and a wooden match to heat it, and no sparks! There seem to be 11 middle rail nubs per switch that could be troublesome. I have another 44 more nubs to do.... but it goes quickly.

Thank you all for the help = another problem solved due to the good people of this forum.

Cheers, John