Desert Forces train not working

[zacktodd]

My boys have a Desert Forces train that is about 2 years old. It has always run well(they do not leave it out all the time).  Recently, the train pauses as it runs, especially at the straight track parts (it is shaped in an oval-7 curved then one straight-then 7 curved-then one straight-16 in all). One car in particular will cause the entire train to stop running-although the rest work well. What can I do to fix it? Is there something connected wrong? I spent an hour staring at each tiny piece to see that the EZ track is connected properly and I believe it is (those little gold connecters get shifted). I'm guessing that there is two problems-one is the obvious not working car and another is something else and I'd like to fix both problems. I know nothing about trains and am stumped at what to do next. Can anyone help?
Thanks!

[SteamGene]

It sounds like you have dirty track.  Take a lintless cloth, put some denature alchohol on it, and rub the track.  Then take a dry rag cloth and wipe it off.  It would be good to clean the wheels too.  You can do this by putting alchohol on the cloth and drape it over the tracks.  Put SOME of the drivers/powered wheels on the cloth and turn on the power while holding the locomotive firmly so it doesn't move.  You will spin the wheels.  Then do the same with the remaing drivers/powered wheels. 
Take your finger and rub it over each track joint, both ways.  You shoould NOT feel a bump.  If you do, you have a piece of track resting on top of a joiner.  This is not good.
Gene

[zacktodd]

Will try-thanks so much!