I was able to find a caliper, just waiting for it to come in the mail.
On a side note, I've been working on the comet cab car, and have some pictures.
This is what it looks like so far.
pinterest.com/pin/130956301637195083/
I've been primarily focused on the crappy Walthers trucks. I found a guy who suggested to take brass piping and glue it into the plastic holdings for the axle. I did a few, here is a shot of one of them.
pinterest.com/pin/130956301637195098/
The post I found talks about the Amfleet cars, but if you notice, the trucks are exactly the same. This guy's tutorial has great photos and instructions to do the job.
geekhobbyist.wordpress.com/2011/12/26/walthers-amfleet-truck-modification/
Only difference for me was I kept the brass piping a solid piece, instead of cutting the pieces into bushings. I feel, for now, that works well.
I'm getting a TCS lights only decoder and keep alive for it. I will post pictures when I get it installed.