redboy is a shuttlewagon, a brand of "mobile railcar mover"
back when rail was king, lots of industries could afford to have their own small switching/shunting locomotive to support their industry, but a locomotive (even a small one) is a costly thing to maintain. mobile railcar movers are basically tractors on rails, often sport rubber tired wheels for both traction and the ability to be moved off rail, etc.
NASA and the Air Force each sported their own fleets of locomotives to run on the 60-odd miles of rail laid across the space center, and to this interchange point with the Florida East Coast Railway that I'm currently staking out. this is the sole rail connection for the entire space center, this drawbridge.
I've talked about the Air Force's locomotives (and their mobile railcar mover replacements) in this post about my favorite video.
NASA at first had some old ALCO SW2s, but replaced them with EMD SW1500s ahead of the Shuttle program. Just as Titan spelled the end for the Air Force switchers, the end of Shuttle brought an end for the NASA ones, as the railroad was mothballed in the early 2010s. one leg of it was even ripped up, the line along the ocean to the air force base that Titan once used.
funnily enough, the guy whose brightline construction videos I watch was invited with his railway group to document some of the last days of operations for the KSC Rwy, and he's got a video of it.
all the locos were sold off or donated to preservation by the mid 2010s, a lot of the rolling stock was shifted around to government agencies, SpaceX bought some of the helium tank cars to use for their launchpad funnily enough.
so when SLS is finally ready towards 2020, NASA doesn't have a locomotive to receive the SRB segments anymore, or switch them around on base. The FEC would generally only drop them here at the yard on the mainland, that's their interchange point.
so, like Lockheed when the Titan locos weren't an option, NASA looked to a mobile railcar mover. it's cute.
it's really very much a tractor on rails and we love that for it.
