In 1901 the promoters touted it as the Leatherstocking Route (alluding to James Fenimore Cooper‘s novel) and extended 25 miles northward to Cooperstown. Finally, in 1902 they extended the line to Richfield Springs (then known as Richfield Spa) and in 1904 to Mohawk. This created a 52-mile main line from Oneonta to the banks of the Mohawk River, and left Cooperstown on a three-mile branch from Index. For several years, the D&H had an injunction preventing the electric line from crossing the steam line at the west edge of Cooperstown. Passengers were obliged to walk across the railroad between connecting electric cars.
Although short on population, the Southern New York had connections with the Delaware & Hudson and the Ulster & Delaware at Oneonta; the Delaware Lackawanna & Western at Richfield Springs; and the New York State Railways and West Shore at Mohawk.
The company built a coal-fired steam plant at Hartwick to generate electricity. Because of the growing dependence on the profitability of power, the name of the company was changed in 1916 to Southern New York Power and Railway Company. The power business went on its own in 1926 and the line became Southern New York Railway. When the power business split off, though, so did the profits. The first casualty was Oneonta city trolley service. In 1922 there were five round trips a day between Oneonta and Mohawk. This was reduced to two by 1930 and then to one. The 1933 abandonment of the Utica and Mohawk Valley subsidiary of New York State Railways left the SNY without Herkimer access, a New York Central connection, and interurban box motor service to Utica. Passenger service was terminated and the line was cut north of the company-owned Jordanville quarry. Electric freight service lasted another seven years. The major justification for freight service was the quarry. When the quarry closed, the Southern New York then dropped back to a three-mile long diesel freight connector with the Delaware & Hudson at Oneonta.
Early into the excursion, a car ran into the trolley at an intersection. Damage was light, as the motorman quickly dumped the air. The car was owned by the mayor of Richfield Springs, who proclaimed, “There aren’t any trains on this railroad on Sunday!” He ended up joining the trip.
Also joining the trip at Index Junction was famed photographer Arthur J. “Putt” Telfer of Cooperstown. His pictures of the Southern New York portray the entire history of the line and are preserved in at least two museums, as well as in the collections of several postcard collectors. Telfer focused each print with his head beneath a black shroud over his old-fashioned (even by 1938 standards) camera with leather bellows.