Cheryl,
This is the Crain Highway monument, erected in 1922 in celebration of the beginning of construction of the new Crain Highway. The road was completed and opened in 1927. We have a full report on the monument (description and history), but since our library is at the moment in the process of moving into the Greenbelt Public Library building, it will be easier for you to get the report on the web. I have left a phone number on your home phone - call me, and I'll tell you how to get the report on the web.
There were two railroads that came through Upper Marlboro, but they have nothing to do with the monument. The Pope's Creek line of the Baltimore and Potomac RR was opened in 1873, connecting the markets of Baltimore with southern Maryland; that line (now CSX) still runs through town (used only for freight now), crossing Marlboro Pike just east of MD 202. Another railroad, the Chesapeake Beach RR, was opened in 1898/99, connecting Washington, D.C., with the developing resort town of Chesapeake Beach on the Chesapeake Bay. The resort and the railroad suffered failure during the Great Depression, and the railroad ceased to operate (and the tracks were removed)in 1935.
Hope this information helps!

Susan G. Pearl, Historian
Prince George's County Historical Society

--Previous Message--
: Am looking for any information on the railroad
: that ran through Uppr Marlboro for which a
: monument was erected in the town of Upr
: Marlboro.
: It sits at junction of Old Crain Highway,
: Main st and Marlboro Pike.
: