Thanks folks!
As to the tank car height. I only have four of such cars so if the platform height works for them I think I'm good to go.
I have Liquid Electrical Tape and have used it for just those kinds of issues. I have to get some more since my bottle is getting too thick. I may revert to using it if the shrink tubes don't do the job.
Speaking of shrink tubing, I have a neat tool that I bought at Radio Shack (you remember those...). It's a hot air gun specifically designed to heat shrink tubing and it's a terrific time and finger saver. It has a metal shield that wraps around the wire so it heats all around and keeps the hot air from blowing on you.
I may have a problem with this thicker cable when I run out of the very thin wall tubing and use the more normal thicker wall K-S tubing. If it doesn't work, I have some finer gauge red wire that I can run down the tube and tie the zip cord to the bottom. I have to add the resistor and that could be a convenient place to splice the two leads together.
