The Rensselaer and Saratoga Railroad was chartered on April 14, 1832. It completed 25.2 miles (40.6 km) between Troy and Ballston Spa on March 19, 1836.
The railroad was largely conceived and built by businessmen of Troy in response to Albany's construction of the Mohawk and Hudson Railroad and the extension to Saratoga called the Saratoga and Schenectady Railroad. Despite its name, the railroad only reached to Ballston Spa and relied on the Saratoga and Schenectady to give it access to Saratoga Springs, New York. When an agreement was not forthcoming, investors seized an opportunity to buy up Saratoga and Schenectady stock and take control of the railroad.