Hmm...a little more trial and error, and I have to amend my inclinations...

I don't think it's the transformer, but now the controller itself.  Rather than change the wall outlet the transformer was plugged in at, I tried unplugging the transformer from the controller.  Waited a few seconds and plugged it back in, and Thomas would run.  The same wasn't the case when I unplugged the line to the track, so I'm led to believe the controller is at fault.

Curious thing, if I have it set to 100, plug it in, Thomas goes and keeps on going, indefinitely as far as I've been able to tell.  Only when I turn it down, even as little as to 95 or 90, he'll come to a stop.  If I immediately go from 100 to 0, he keeps moving, too...not just for decceleration, but even after that there's a small crawl.  Yet, no other lower setting will work -- turn it up to 20 and he's back stopped.

I ran the train at 100 for a few minutes -- the engine didn't get hot, but the controller did.  That's probably where I'm going to look next.

I'm not sure -- it's certainly possible, but I don't think it would be a lubrication issue.  When it has decided to work, the engine has taken off with no hesitation, no pull like it's working itself loose.  There's no hum like if the motor's working but it's impeded, either.  And after it does run, the engine hasn't seemed noticeably warm and certainly no smoke to speak of. 

Regardless, it's probably a good idea to check its lubrication anyway, so I'll be sure to do that, too.  Thanks for the advice.

I'm having some problems with Thomas working consistently and wanted to run it by in case others have had the same problem and I'm heading in the wrong direction.

Anyway, we got my son the Deluxe Thomas w/ Annie & Clarabell set for his 1st b-day (2.5 yrs ago).  First couple uses no problem...packed it up and put it away, then tried it again about a year later, and it wouldn't run at all.  I just put it together again after another year or so, and it still wouldn't work.  Checked the track connections, all that good stuff, and all that was fine.

Just for kicks, I got a regular current tester you'd use for a regular wall socket, thinking it might work on the rails.  It didn't, but when I used it on the outlet, and replaced the transformer to the wall, Thomas all of a sudden took off again.  It lasted for about 15-20 seconds and fizzed out again, but every time I would change outlets like that seemed to buy Thomas a few seconds of life.

So, while I haven't ruled out an engine problem entirely, I'm looking at either the controller or the transformer.  The controller is a simple blue unit, radial dial (0 to 100), with a direction switch above it and accessory jacks on top (item 46604A).  I've ruled out a short in the cord from controller to track.  The transformer is a Sandan AC120V/60Hz/24W --> AC16V/1000mA/16VA.  In other words, all original equipment to the set. 

I'm leaning towards thinking the transformer is bad but I'm no electrician.   Like I said, I haven't completely thrown out the idea that it's the engine.  Just wanted to see if anybody had similar issues (maybe there was a bad run of transformers or Thomas engines manufactured 3-4 years ago?) before I bothered to go get a new transformer.

Thanks in advance!