I found this print on eBay recently and am quite pleased to add it to the Georgetown Branch collection. The caption on the back of the 8×10 print reads: “1/59 Washington, DC – Line #20 – B&O RR trestle – crossing over Cabin John line.” The photo was taken from the west side of the trestle, facing to the east.
At the time, the Dalecarlia Reservoir was undergoing a massive expansion project. Aerial photos from 1949 and 1957 show the scale of the expansion.
The last trolley on the Cabin John Line was on Jan 3, 1960, and the entire system was fully closed in 1962. Congress revoked its charter in 1956, so likely seeing the writing on the wall, the Dalecarlia reservoir began expansion in the mid 1950s. The right of way was repurposed and is where some major buildings and two of the settling ponds exist today.
Hope you enjoy this brief view of the bridges over the trolley line. If only there was a train passing by! 🙂