The track map below refers to the New York Railways "Eight Avenue" streetcar line in Manhattan. According to Linder, the exact date of the start of horse car service is not known but the 1855 date is the date that the company bought from the owners the road from Barclay Street to 59th Street. The line was extended in stages to 159th Street and Eight Avenue in 1897. Portions of the line were electrified in 1898.
The Eighth Avenue streetcar line does not follow the Eighth Avenue Subway directly that runs under it, but they share some common streets such as Eight Avenue in midtown and a portion of uptown. The IND (Eighth Avenue) subway opened in 1932 but construction started in 1925. Since the construction was mainly of the "cut and cover" kind, this would mean that the surface had to be turn up, including the trolley tracks and its' underground conduit. Since according to Linder, there does not appear to have been major disturbances to streetcar service during construction (at least as explained in his brief article), streetcar service may have run on temporary tracks. At any rate, by 1932, perhaps new track was installed on the surface of Eighth Avenue. It is ironic that three years later, in 1935, the line was abandoned even though the track was relatively new.
Around 1904, a branch of the Eighth Avenue Streetcar opened to the Cortlandt Street ferry via Greenwich Street, Dey Street Washington Street and Cortlandt Street. If you look at the downtown portion of the map, you can see the curve at Fulton Street and Church Street. Fulton Street used to run from river to river. The Fulton - Church Street intersection was at the entrance to the old World Trade Center. Of course, before the development of the first World Trade Center, the street pattern was different and you had in the area a lot of electronics stores. With the construction of the World Trade Center superblock in the late 1960's, the smaller streets at the site were eliminated. This was the area of the historic Corlandt Street Ferry.