Uncoupling problem when passing over 072 switch

If your switch is the original Lionel 711 style, the tip of the wide center rail is making contact with the sliding shoe. I solved the problem by putting a small piece of electrical tape on the end of the rail. This may possibly also occur on other brands and ages of 072 switches. BTW, the earlier the postwar sliding shoe, the more likely some 711 switches are to just pull the shoe off the bottom of the truck as there is a place where the early shoes can get snagged near the frog.

I tried your tape fix and it seems to work!  Thank you very much.  I'm curious why only two of my six passenger cars kept uncoupling, I guess their hot shoes are aligned a bit differently.  Do you have a problem with the tape wearing out ?

With use the ridges (sides) of the shoe wear which allows the hot rail of the switch to penetrate the gap and touch the activating rivet in the gap of the shoe. Some reproduction shoes are not manufactured to the standards of originals and have larger gaps with no seat for the rivet and larger rivet heads which creates the problem you are experiencing. While the tape solution will work it can cause some E units in locomotives with short roller spacing to sequence. A permanent fix is to file or grind the rivet head almost flush with the shoe leaving enough metal to secure the shoe. Even if it is flush it will contact the activation rail of a UCS track and open the coupler. You can file the rivet head with a round hand file but a rotary tool is much faster. Either method will spread some residual metal that will secure the shoe. I have been doing this for years. It always works and I have never had a shoe come off.

Thanks for the tip.  I have quite a few cars to inspect and my daughter has a dremel that should be a good tool for the job.

I use a small cable tie to hold the shoe up. It goes in the shoe's groove and around the coupler plate. You can always snip the tie to restore it to original function. Grinding it down is a one way street. 

Alan

Clear, dental (braces) rubber bands from the big river site.

There is obviously more than one way to cure the problem. I prefer to file or grind the rivet because the coupler remains functional and you can conduct switching operations. I don't agree that it is a one way street. Although I have never lost one due to this procedure they are replaceable. I have replaced many when rehabilitating old trains. 

RRS posted:

I tried your tape fix and it seems to work!  Thank you very much.  I'm curious why only two of my six passenger cars kept uncoupling, I guess their hot shoes are aligned a bit differently.  Do you have a problem with the tape wearing out ?

I have yet to have the tape wear out or let go of the rail. I did clean the rail with 91% rubbing alcohol before putting on the tape. 1946 flying shoe type trucks seem to snag frequently on the switches. I think Lionel knew of the problem back then, because many of the flying shoe type trucks have a metal backer for the pick up shoe rivet instead of the usual fiber board. Also happens to the later versions of the pick up shoe equipped cars. The closer to 1950 vintage, the less and less it happens in my experience.

Several on the forum have suggested using clear nail polish but it needs renewal every so often.  Good to know BIGO's tape will last, so I think I will try it too.  I have several log dump cars that will do a quick activation when the nail polish wears down.  Seems it should fix that too.