The Suncook Valley Railroad
The Suncook Valley Railroad was originally chartered in 1863 to build a line through Suncook Valley, running between Suncook and Alton Bay via Pittsfield, in New Hampshire. (Both the Suncook Valley Railroad, to run between Suncook and Pittsfield, and the Suncook Valley Extension Railroad, to run between Pittsfield to Alton, were chartered separately but intended to be a singular right-of-way.) The line between Suncook and Pittsfield was built in 1869, with the remainder of the line, only reaching as far as Center Barnstead, completed 20 years later.
The line came under the control of the Boston and Maine Railroad in 1895, who elected to abandon the entire route in 1924. Local opposition to the abandonment prompted B&M to instead sell the line, which continued operation as an independent company under the Suncook Valley Railroad moniker. However, rising costs of operation and the increasing prevalence of the automobile spelled eventual doom for the railroad. The Pittsfield-Center Barnstead segment was abandoned in 1947, with the remainder of the line following in 1952.
The right-of-way is notable for using a switchback to climb the grade up from the Merrimack River into Suncook proper from a connection with the B&M Concord-Hooksett line, also abandoned.
The northeastern terminus of the Suncook Valley Railroad was Center Barnstead, NH, not Barnstead, a little farther west. Also, I THINK the shorter leg between Suncook and Bow Junction, NH, was owned by the Boston & Maine RR, having been taken over in 1895 from the Concord & Montreal RR (formerly the Concord Railroad).