On the Hi-Rail, O27 and Traditional 3-Rail O Gauge forum there is a post about the original railscope.
Gunrunnerjohn has an ebay link'
http://www.ebay.com/itm/Wirele...;hash=item58a0037491
I found this on ebay.
http://www.ebay.com/itm/5-Inch...;hash=item2a4620d2f9
So for a little over $40.00 you can get a camera, transmitter and 5” monitor.
I’m thinking the grandkids would love to see the train running on the layout and then looking at the monitor to see what the “engineer” sees.
It should not be very hard to mount the camera on an old engine or a flat car install a 2amp or so full-wave bridge rectifier, a capacitor to smooth out the current and a DC/DC power supply set to 12 volts such as;
http://www.ebay.com/itm/LM317-...;hash=item3f4350b591
If you have the room on your layout you could make a drive in theatre and frame out the monitor as its screen.
I have my order sent to ebay. I’ll report back how it works out.
Greg
PS, John if you read this, what size cap. would be about right?