Forgot to mention I used to build dioramas as a hobby min Middle/high school, go fairly decent at it, now I wish I still had them (like just about every other person in America, I think my mom threw them out at some point). I can appreciate some of the detail you put into your work, especially the weathering techniques.
To roll it back a bit. I grew up near the U.S. Naval Ordnance Station in Indian Head MD (I think its the Naval Surface Warfare Center Indian Head these days); my Dad worked there from 1951 to 1988.
The base itself had quite a few spurs going everywhere, but they all joined a central line that went from the base itself through Charles County MD to White Plains MD, where it joined with a branch of the Pennsylvania Railroad and finally CSX. As a kid in the 1970s I recall that locomotive (and one in battleship gray) traversing the tracks from time to time, but never bringing in cars (by this time, it was easier to truck things down via Route 210). The base also used the locomotives for various open-house events where they used them to conduct tours.
At one point, some entrepreneur tried to use the line for a dining car service, but given its only 13 miles of track, they had to go fairly slow. They used an old EMD E-units and converted LIRR passenger cars for dining. The venture failed, the EMD locos ended up at a power plant at the end of the branch (think they are still there to this day) and dozens of LIRR passenger cars were stored on old quarry tracks in Waldorf before they were scrapped in place (CSX refused to haul them because they were poorly-maintained and derailed every time they tried)
At some point the DoD transferred the line to Charles County MD, which converted it to a rail-trail. The soon-to-be-stranded locmotives on base were auctioned off (the one in the photo plus an EMD SW8 that had been transferred from the Army's Aberdeen Proving Grounds). Both ended up being trucked out.
As a bit of a side-note of history, once the rail trail was up and operational, the Charles County Government acquired a vintage sign from the slot machine era (1946-1968) that was restored and became the entrance sign to the rail trail
This is how the sign looked back in the day, presumably the arrows went on-off in sequence
And how it looks today
