Dirty Track...

Particularly if it's the black roadbed, steel rail stuff, you have to clean it well, and often.  If the track is really oxidized or joiners are loose you may have bad connections between sections.  I have a loop of the black roadbed EZ Track that I let my youngest run a train around.  It needs cleaning before each use without fail, even if it was cleaned yesterday.

You may also need to clean the pickup wheels on the loco.

Nickel silver rail is much better, but all rail needs to be clean.  The gray roadbed EZ Track is nickel silver rail.

Just my guesses...

I think you're right on the

I think you're right on the mark.  I went and kept playing with it.  I kept running it until it stopped.  Looked at it very close never saw anything wrong.  after a few passes it started to get past the 2 points with a little hic-up but eventually it was running without stopping.

What is the best way to clean the track?

Oh and yes, it's the black road bed but the rails don't look dirty or oxidized at all.

Surgical clean!

If the track is really bad, a bright boy or VERY fine (like 1000 grit or finer) sandpaper might be needed.  You might also have good luck with chemicals.  When I was a kid, we used a product called Energene (maybe carbon tet?) to clean steel Lionel O27 track.  If you do use a liquid, make SURE it is not oil, and that it leaves no residue.  If you use an abrasive, use a super fine one, or you'll leave scratches in the track which will end up making things worse in the long run.

Read the Dec. 2012 issue of MRH and consider making a Masonite slider.  They are excellent at keeping track clean, and it would probably be a good idea to put one in your Christmas train.

Whatever you do, aim for a mirror polish on the rails.  If they're not super shiny, they're not clean.  If they're dull, they're either oxidized or pitted/scratched, and while that will help with traction it will prevent good conduction.  Also do not forget to clean the wheels on your locos and cars.  If you have plastic wheels, they will attract all sorts of nasty gunk.  Metal wheels can be cleaned effectively with lacquer thinner, but plastic wheels need something a bit less aggressive.  Denatured alcohol or Windex tend to work fairly well in my experience.

Changing power packs should not make a difference, unless the one you have is simply not powerful enough for your loco.  What will help is adding a second terminal track and a second set of feeders 1/2 way around the loop.  If you notice the engine slowing down at the far point and then speeding up again, the resistance in the rails is causing a drop in voltage at the far end.  More feeders will help a lot, but be sure to keep them wired the same way or you'll have a dead short.

Finally, you might want to practice putting rolling stock on the track without the use of the re-railer.  HO rolling stock is not as robust as the larger O and G scale stuff, and it doesn't just plop itself on the track.  It's not hard to get one wheel off the track and not notice it if you're not paying attention.  Since you mentioned derailing, I'm guessing that's what's going on, especially since you said you carefully checked every track joint.  Also, locos do not like being pushed back and forth, and some people will say it can cause cracked or split gears or other internal damage.  I'm not convinced that a couple inches now and then will destroy a decent mechanism, but I still try not to slide the wheels if I can help it.

Cleaning Track

Contrary to what others do, I stay away from any abrasive cleaning methods.  What I have been doing with success on my sons EZ Track is to use rubbing alcohol on a cotton cloth to clean the rails.  They will not look dirty but you will see the black that comes off.  Cleaning the wheels is important to.  Do keep in mind that the alcohol is flammable though.

Others use mineral spirits and there is a product called No-Ox-ID that is supposed to be really good for cleaning rails and keeping them clean.  I have yet to try it.  Avoid any solvents that will melt plastic of course.

I find that once I can get the locomotive to run that the track actually improves with more running. 

For what it is worth,  I would go to nickel silver flex track for the permanent layout and use the EZ Track around the tree and to get a train running today.

On abrasives

Abrasive track cleaning methods should, in my humble opinion, be reserved for those cases where things are so bad that no amount of solvent will solve the problem.  However, as mentioned in my post above, you must take care to leave the rails polished in the end.  What happens, as I understand it, is that the fine scratches greatly increase the surface are of the rail, and thus it oxidizes more and faster.  If for some reason you have to sand the track, or even use a bright boy, I would at least rub a piece of Masonite over it afterward.  Masonite is mildly abrasive (about as much as paper) and will help to polish the rail.  The way I see it, if the result is a nice clean polished rail, the scratches should be mostly gone.

I look at it like a paint job on a car.  Sometimes you have to use coarse sandpaper on the body work, but in the end you have to finish with rubbing compound, or you'll have a sub-standard product.  It's a lot of work if you start with something course and aggressive, and that should only be used when absolutely needed.  The rest of the time, use milder options which do the job with less hassle.

Thanks a ton, guys.  I've

Thanks a ton, guys.  I've done a little wiping with a paper towel and some alcohol and it's running better already.  tomorrow i'll give it a better cleaning and do the wheels.

Flex track is definitely going on the permanent lay-out and this set up will go into a box until next year, lol.

Good to hear...

Glad you are getting somewhere with the track cleaning.

Ken, I don't mean to say you are wrong about abrasives and you are right on the money, polishing out the scratches will work fine, but it's a lot of work.

That said, in my limited experience I have never seen track so dirty that no amount of solvent could clean it.  Even my old brass sectional track never got that bad.  Not saying it can't happen, I just have not experienced it.

When it all goes south

One word, Kevin.  Rust.  Steel track rusts, and once it's rusty you pretty much have to sand it clean in my experience.  Replacement is usually a better option in that case, but sometimes there is no time or budget for that, and you do what you have to.

Other than that, I agree - chemical cleaning is the way to go!

Rusty Rails

I could see where you might have to use an abrasive to remove rust.  That's something I will have to watch for.

I would have thought that if EZ Track was going to rust, I would have seen it by now.  We had flooding issues a couple of years back and while the track was never soaking in water, the humidity in the basement was off the charts, yet no sign that the track rusted at all.  Still, as you say, if the rails are steel, under the right conditions rust is going to form.

Nickel Silver EZ track

I have both types of the Bachmann EZ track and the nickel silver track is much easier to maintain as far as cleaning goes. The steel track seems to need a lot of TLC and attention. I have a small 4x8 layout that I am using the nickel silver track on and I have had very few issues with it. I plan on using the nickel silver EZ track when I build my new layout as well. I have also replaced all of the plastic wheelsets on my rolling stock with metal wheelsets. I read a very interesting article on the MNRA website about metal vs. plastic wheelsets and it seems that using plastic wheelsets causes dirt and crud to build up on any type of track much, much faster. I have a copy of the article if anyone is interested, I can post it here.

My take on EZ Track is that

My take on EZ Track is that the best thing to clean it with is a sledgehammer. Pound repeatedly until the rails are bright and shiny, then move it to the recycling bin.

Kato Unitrack is a far superior product, with a much greater variety of pieces available, and needs much less cleaning. It's also darn near bulletproof, and the joiners are replaceable, not molded into the track. It's the standard for T-Trak modules, and a number of people are using it for N-Trak yards as well. The HO Unitrack uses exactly the same connectors. The difference in price isn't that significant, and the quality more than makes up for that difference. Track is one of those areas in model railroading in which spending a little more can make a world of difference in the satisfaction and pleasure you get, and for a child, especially, it's worth it. As little as you're going to need to go around a tree, it's not a major expense.