Very basic question...

Your issue involvoles all three engines. I would first connect the transformer wires to your engines to see if they run well. If all goes well I would check out the track. Inspect the center rail card stock for damage causing a short. You can also put all 6 or 8 sections of the straights together and see if you have a problem. If you do then remove one section at a time and see if the problem goes away. Process of elimination until you come across the bad track section. What you described screams a track problem to me. 

Big assumption on my part is you have tried to run only the engine on the track, no tender and drawbar is not touching the outer rail and your still having a problem.

Hello Stew--

Thanks for taking the time to reply. I have run the engines by themselves, and while it does circle the layout, there is a bit of hesitation around the 2 curves.

I have not tried touching the wires directly to the locomotive--that requires three hands!

I suspect that you have several issues going on.

I think a sixty watt transformer Is rather small for a 681 or 682. IMHO, it's barely large enough for your 2036. The transformer getting hot is also a good indicator.

The problem with an undersized transformer is probably compounded by dirty track.

In addition to cleaning your tracks with a track eraser, I suggest some additional cleaning with a solvent. I use a small amount of pure mineral spirits on a tightly woven cloth. (Be certain to dispose of the cloth properly, and do in a ventilated area).

I would also clean the locomotive drive wheels and pickup rollers with that cloth.

How difficult would it be to disconnect your ZW and try that?

Your 1053 transformer does have an internal circuit breaker. If you had a short it is likely to trip. Plus, its likely that the train would not move at all with a short.
Carefully feel around the track for a hot spot. Slide your hand along slowly, feeling for the track to be getting warmer, because a hot spot can be hot enough to burn instantly. A hot spot could be a short, or a high resistance (poor) electrical connection.

Thanks for all the replies. It's still too early here for me to start making noise, but I can confirm that there are no hot spots; I checked for those last night. I didn't note any missing pieces of center rail insulation. If that were the case, wouldn't there be sparking/tripped circuit/train not running at all, as someone mentioned?

I am hoping it's a simple case of dirty track and or drive wheels/pickup rollers, though I cleaned those pretty well (two and three different times). The volt meter is an excellent suggestion so as to deduce the culprit here. I am embarrassed to admit that I am terrible with electronics, and I am not very quick with the volt meter. What voltage should I be looking for?

The fact that the transformer--being run with the throttle at full power--gets hot but yet the locomotive doesn't: what problem does that point to? From my experience with trains, not only the bottom of the engine, but the locomotive shell gets quite warm after just a few minutes of pulling cars around the tracks, but yet the bottom of my 681 is just barely warm to the touch after 20 minutes of circling the tracks and being aided through the problem curve in question.

Thanks again.

Also to clarify, I did use the 1053 for the past two holiday seasons with all three of these locomotives and a string of tender/caboose/3 other cars with no problems at 60% or so throttle. (Not to mention doing same as kid all through the 1970s, though that was a very long time ago.) Now at 100% throttle the locomotive alone makes it around the loop, but not with more than 2 or 3 cars attached.

Is it possible that the transformer is failing/windings are corroding, or would the transformer simply not work at all?

I would try checking the track advice that Stew1957 gave and put s few pieces together, place one engine on 4-5 pieces, change/add track on until you can see if all your track is good.

CW mentioned the mineral spirits, also good advice. If you don't have that, I am a big fan of Goo Gone which you can use it on the track, locomotive drive wheels and rollers. No fumes and citrus based. Before everyone disagrees, your locos are all postwar, mine are mostly prewar. As long as you don't have modern engines with traction tires, the Goo Gone is fine. Use a white cloth if you can and check how much gunk you are getting off.

Keep everyone posted and show pictures when things are running.

Tom 

quote:

The fact that the transformer--being run with the throttle at full power--gets hot but yet the locomotive doesn't: what problem does that point to? From my experience with trains, not only the bottom of the engine, but the locomotive shell gets quite warm after just a few minutes of pulling cars around the tracks, but yet the bottom of my 681 is just barely warm to the touch after 20 minutes of circling the tracks and being aided through the problem curve in question.

Not a common problem, I guess it's possible that your transformer is going bad. You can try disconnecting the transformer from the tracks, and plugging it in for the 20 minutes you mentioned above, and see how warm it gets. DON'T LEAVE IT UNATTENDED. It might get a little warm, but it should not get hot.

The Lionel 5C test bench had a "Watt Loss Test", which put a 60 watt household bulb in series with the primary of the transformer being tested. The bulb should not light with a healthy unloaded transformer. It is interesting to watch the bulb get brighter and brighter as the transformer is loaded up. (I am not suggesting you try to set up this test)

I would have some concerns if a locomotive that I was servicing got quite warm after only a few minutes of running.

With transformer disconnected from the track and nothing on the bare track, check the OHMS between the center rail and either outside rail. If the reading is infinity, the transformer is the culprit; any other reading says there is a bad section of track. To find the bad section, disconnect the circle into halves and test each half. Repeat the halving process and identify the bad section. Worst case scenario for number of tries  is half the number of sections.   

I note that you have done a lot of cleaning, have you done any lubricating?

Gentlemen:

I discovered this morning that the batteries were dead in my multimeter; it appeared to be yet another disappointment and thus I decided to spend Sunday doing other things. I appreciate the advice, and I will report back mid-week.

PS--I have not done any lubricating; excellent advice