Issues with E-Unit vs. Switches

Jeff you need to turn your e-unit off if you can and make sure its in foward when you turn e-unit off they will not do that. 

Yes i have the 1666e gun metal Lionel engine and it does the same thing , you can just put the "E" unit switch off ounce you leave it set to forward and it might just pause for second as the roller on the older switch's the center rail of the roller loses contact as when they made the switch Lionel left to much gap between the center rail in front and behind the center rail. this is what causes the problem with intermittent voltage to the E unit which is hence is why your loco changes direction or goes int to neutral.some engine's work better then others because they have more then one pickup roller so the other locos don't get a power interruption and continue with no problem>!

Alan
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If you could add a roller to the tender, or if the tender already has a roller, add a jumper between the loco and tender roller circuits and the problem will be solved.  I did that on some of my old Lionel.

Sounds like one of the collector shoes isn't making good contact with the center rail. You can try cleaning them. Check to make certain both shoes have about the same tension.

I would check the following:

Ensure the wires are properly connected to each pickup roller.

Make sure you lightly oil each roller as it helps with connectivity.

When the loc stops on the switch, from that position, lay it down on its side and see where the pickup rollers are in relation to the track.  Is at least one roller on a center rail for power?  If so, that's the roller that is having a pick up problem.

If you see that both rollers are on dead spots on the switches, I would add/use a pickup roller from the tender and run a wire to the engine (as others have stated above).

The 1666 came with slide shoes, as opposed to rollers.

The slide shoes are held in place by a metal strip. The strip also provides the spring pressure, and electrical contact.
I guess the area between the shoe and metal strip could be oxidized.

It wouldn't hurt to remove the shoe, and polish the strip. I'd start with strip of index card, moistened with contact cleaner. Just slip it between the metal strip and the fiber plate. Work it back and forth a bit. In my experience, this will not harm the fiber plate.
If it seems really bad, use a strip of fine abrasive paper. I typically use emery paper. .

The Lionel service manual explains how to remove the shoes. While the manual pictures the process with the plate removed from the motor assembly, it is not necessary to do so. Don't try to remove the fiber plate. It is very difficult to remove a plate without damaging it. And even more difficult to install.
The tension can also be adjusted without removing the plate, but one must have the right tools. I use either contact adjusters that were made for relays, and sold through pinball machine parts supply houses. Or I use specialty pliers that have very small, thin jaws with a very small portion bent at the tip.

The company from which I purchased my relay adjustment tools is long gone (Wico), and I have not seen the same tools on any other supply house's sites. Pinball Resouce has one. I don't know whether it would do the job.  Wico used to sell an assortment of four, all with different bends. Plus I modified one or two for various uses. As I write this, I think the one I use to adjust the fiber plate spring tension is customized.

Here are a couple of pictures of those relay adjustment tools.

Excellent suggestions and help.   Thank you VERY much!!!!

Jeff

As others have said, sometimes with old equipment that is not really compatible (mechanically) with newer track, the E unit will cycle when there is a loss of power from not only an open circuit (no power from the rollers) but also can occur when the wheels or rollers create a momentary short circuit.

I second the suggestion to try, at least temporarily, putting a wire between the loco and the tender.  You can even use a test lead with alligator clips, if you want to see quickly what's happening. That will prove or disprove if the problem is an open. If that doesn't help, you'll need to do some trouble shooting with an ammeter. Put the loco in neutral, power the track, and slowly push the loco through the switch. Watch the ammeter, wired in series with the track circuit, and see if it suddenly indicates a much higher reading. That will be the short circuit you're looking for.  For this application an analog meter is better than a digital one.

In either event, (open or short) try to identify the exact spot where it happens and then see if there is some track issue at that point. An open can be fixed with a loco-to-tender jumper, and a short will require putting some nail polish on the offending section of third rail that's hitting the inside of a driver (just a guess.)

Unless I missed it, you did not state exactly what type of switch tracks you have. If Lionel 022 then there is a spot on the end of the wide center rail that gets pushed down over the years. If this spot isn't raised to the proper level then engines with minimal spacing between pick ups don't bridge the gap. Sometimes it just takes a fraction of an upward bend to solve your type of problem. Modern switches offer other issues as there seems to be little concern for placement of pick ups on modern equipment vs where the gap lines up on switches. I know first hand.... See circled area in photo below.

I didn't mention the period switch, they are #21s...very similar by appearance...and fastrack.    I'll have to check that out.   Thanks.

That jumper sounds like a good idea and easy to do as the tender already has a pick up roller.

Thank you again.   ALL GREAT suggestions.

Jeff

Even if a tender does not have a pickup roller, you can use an "idler car" for the test. Use a lighted caboose, for instance, or a short passenger car. Taking the body off the car helps in getting the alligator clip on the power wire more easily.