In my opinion, the photo was taken on the Capital Transit right-of-way for the Glen Echo line.
The photographer is looking due east, to the point where the right-of-way joins Prospect Street, N.W., not "N" Street. The yellow house at that corner is recognizable, as is the bulk of Georgetown's Edmund A. Walsh Building, looming on the skyline, one block beyond the car. The motorman is changing from the overhead wires that ran from west from 37th and Prospect, N.W., to Glen Echo to the underground connection for the line that ran through Georgetown. "N" Street did not have a street car line, although "O" and "P" streets did.