In the spring of 1854, construction continued, with the railroad reaching Barnstable village May 8, Yarmouth Port May 19, and finally Hyannis on July 8, 1854. Connecting steamboat service to Nantucket commenced from Hyannis in late September and would continue until 1872, when the railroad branch to Woods Hole was opened.
The Cape Cod Central Railroad was incorporated 1861 as a branch from the Cape Cod Railroad, running from Yarmouth east and northeast to Orleans, and opening in 1865. The Cape Cod Central was purchased by the Cape Cod Railroad April 21, 1868, and the two railroads were consolidated on July 28, 1868.
The newly formed Old Colony Railroad extended the line to Provincetown, at the tip of Cape Cod, opening July 23, 1873.