Anyone ever hear about post war dummy A unit diesels that uncouple from the car behind it when cross a Fastrack switch?
Half the time, the Dummy A unit crosses the fast track switch, there is a spark and the coupler opens.
If there is no spark over the switch it stays coupled.
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Depends on which diesel is doing this. What model number?
Post war 2343.
The shoe rides up and over the edge of the center rail and tilts, allowing the rivet head to contact the center rail and thus energizing the coupler coil. I've ground down the rounded rivet top in the shoe groove, flattening it somewhat, using the edge of a cutoff wheel in a Dremel tool. If too much of the rivet head is removed, that head won't contact activating rails on RCS/UCS tracks. That helped on most cars. I've also cut narrow strips of electrician's tape and placed this in the shoe groove, folding the tape ends over each end of the shoe. This was a very big problem for Lionel when electric couplers came into use in 1938. It is why Lionel changed to a non-coil, magnetically activated coupler in 1948 and developed the UCS 5 rail track with an uncoupling magnet in the center.
ok, I see the part you are talking about in the Greenberg repair manual.
Also, I notice 2 of my pick up rollers worn down in the middle.
I tried the electrical tape first, but I can feel it rub against the switch as the dummy passes over. But seems to be working just fine for now.
Most sliding shoe equipped cars do this too.
Rob
I put a tiny piece of cellophane tape over the shoe's contact. I do it on my operating postwar cars, too. Modern switches tend to overkill the length of the power rails needed to prevent dead spots. I do the electrical tape for locos at some Gargraves switches on the center rail.
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