Thanks for all of the comments!
Yes, we know all about the legality... 602 PC (trespassing)... and the danger (minimal--track speed is 25 MPH and we can remove ourselves and the cart in eight seconds; you can see & hear any trains a mile away)...
...and, yes, it is a whole lotta fun! Hope the people who are capable of seeing the "fun" here enjoyed the video. Over 200 miles logged on that cart.
(flanged wheels on my coffin would be cool!)