"Cat hair is optional"
That's one of the reasons the main power for my railroads, for 25 years, was Minitrix Fs. Very little to go wrong, and when it did, very easy to fix. About the only maintenance mine needed was to clean the wheels and remove the cat hair regularly.
With the combination of an electrically "hot" frame and that circuit board for the insulated side wipers, adding jumpers between the units was simple. Solder one end of the wire to the circuit board, and the other to a piece of 1/32 inch brass rod. Drill a 1/32 inch hole in the bottom of the frame of the other unit, stick the rod in it. A solid connection, and easily separated. Just make sure the frames faced opposite directions. With an A-A set, that was automatic. With B units, one had to be careful, but a 4-unit set was almost impossible to stall, even on not-so-clean track. And, in the 70s, the BN in the Northwest still ran solid sets of them, so it fit my layouts perfectly.
Cat whiskers make great CB antennas for N scale vehicles. Use the outer ends, and cut to length. We have a good supply of shed ones. DON'T steal them from the cat!
