Lionel CW-80 temporarily off?

You need to use a different transformer. The lionel CW80 does not work well with some MTH engines and check your wires has good connection and if your using lionel fastrak crimp your center rail on your straights a bit and take your cars off and put one on at a time seems like you have a short in one of your cars.  

Okay, I only have access to my CW-80 transformer and an older model Lionel transformer i don't have the exact name of. Money is tight for me at the moment so purchasing a different transformer is out of the question. I will try the method of putting cars on one by one as soon as I can and I will let you know how that went.

I would try that other transformer if it works to test it.

I have about forty MTH locos of various vintages including PS1 through only a month ago.  All run fine with a CW-80 that is wired correctly, so I seriously doubt that the transformer is the problem.  I keep hearing people say that running MTH locos with a Lionel transformer can cause probably, but like i say i have a lot, and for the past ten years I've had no problems.  

I would check your wiring and the track conections, then look at the locos themselves.  My advice; clean track and wheels and roller swell before doign anything else.  Really well,.

I removed all 4 passenger cars and tried the engine solo and had no problems! I continued to add the cars back and one of them caused the track to short. I will do some further testing with this car to see if it is causing the short. Also, am I in any way damaging the engine or its components when the track shorts like this? I have noticed that after a short, the engine does not make it's start up noises that come with protosound. I am also having troubles with getting the engine out of idle but i believe this is because of the battery being low.

I placed the 3rd car on when i received the short. I have now tried the 4th car and that one is also giving me a short. I tried the two bad cars separately alone with the engine and they both still shorted the track when the horn is pressed. It looks like i have two bad cars? Is there anything I can do to fix these cars and make them usable?  

The short can short something out in the engine and your cars has short check the wire to the lights underneath and your ground strap not touching the wheels and check for bare wires and wires not touching any metal and what is your cars item number and engine.

The engine is MTH item no. 20-2186-1 and the two cars that are shorting out are Lionel 6-19148 and 6-19149