A couple of years ago, I finally found a 4 unit set of MTH Milwaukee Road boxcar electrics at York TCA. As soon as I got home, I put them on the mainline and all was well until they reached the back corner behind a mountain. The noise was indescribable: Pop, screech, crunch. I powered it off and what I saw hit me in the gut. The front pantograph hit a low overpass and was dangling from the lead unit. Since it was an automatic powered pantograph, I was sure that it was wrecked beyond repair.
There was a happy ending thanks to the engineers at MTH who must have anticipated acts of stupidity. It was undamaged and I was able to snap it back into place. It worked!
Now the units run safely under wire on my high mountain electrified track. No more testing on the mainline!
Bob