Re: US Navy steam railroads south of Washington, DC

Interesting that you should write this and these questions. I have been doing some research on the Dahlgren railroad connection between the proving ground and the RF&P and while I can help you a bit, there are still some questions that I would love to have answered also.

Dahlgren had a 2-8-0 #99, which was originally Meridian Lumber Co (Louisiana) #206. It was originally used to haul logs from Sieper, LA to the Meridian mill at Meridian, LA from 1923 to 1928. After the Meridian mill burned in 1928, the locomotive hauled logs from Sieper to the Meridian mill at Alco, LA until Sieper cut out in 1929. The locomotive was put into the Alco engine house and stored as west end protection power for the Red River and Gulf RR (owned by the same people as Meridian). The engine was stored there until 1942 until it was sold to the Navy for Dahlgren.
Sometime after WW2 it disappeared and I don't know what happened to it, but I assume that it was scrapped. Two twins (Baldwin 10-34-E locomotives), Chatahoochee Valley #21 and New Hope and Ivyland #40 survive with #40 running in New Hope right now.