Phil,
This is my home-brew camera car.
After buying some cheap $20 wireless camera and receivers on eBay over the last few years, I finally decided to invest a little more time and $$ into a camera car. I went with equipment typically found on drones used for FPV. I love the picture quality that Digital wireless camera can output, but absolutely can't stand the Lag & Latency they have. Also when the signal dropped the image didn't just get a little fuzzy, it was gone all together. My requirement is a real time image with as little latency as possible and found the using an analog FPV camera fit the bill nicely.
Below are a couple of pictures of my camera car which has been built and rebuilt several times over the last 5 years. I hope this is the last time I have to rebuild this thing and this version is in it for the long haul.
Right away I know what a lot of people are thinking, why are you using batteries!?!! Two reasons:
1) Consistent, clean power without fluctuation or any possible interference to the TMCC or DCS signal. The car can also be placed off track to grab stationary shots without any need for track power.
2) WEIGHT!!! I found that pushing the car without weight caused frequent derailments on curves and switches. Also, the Weight keeps this thing well grounded and it doesn't bounce around a lot, the image stays pretty stable.
I also wanted the camera to turn with the curves so I rigged the mount to the truck to allow it to turn with the truck. When the camera is mounted stationary to the flat car, you tend to get dizzy when the track goes in and out of the picture. Now the center rail stays in the center of the screen... for the most part.
I can post video of the car in operation if you want or a parts list if anyone is interested.