The oldest piece of the Selkirk Subdivision is that northwest of Hoffmans, opened in 1836 by the Utica and Schenectady Railroad.[4] The final piece, from Unionville southeast to Selkirk Yard, was opened in 1924 by the Hudson River Connecting Railroad.[5] With this final opening, the Selkirk Subdivision became a bypass of Albany for traffic between the west and either Boston or New York City. The entire line became part of the New York Central Railroad and Conrail through leases, mergers and takeovers, and was assigned to CSX Transportation in the 1999 breakup of Conrail. (Prior to the breakup, Conrail's Selkirk Branch ran from the Hudson Subdivision in Stuyvesant north and west along what are now known as the Schodack Subdivision and Castleton Subdivision before reaching the current Selkirk Subdivision, and ended at Hoffmans.[6])
