Horses initially pulled railway carriages, followed by a conversion to steam engines, then on to battery-powered Julien electric traction cars.

As of 2017, Metro-North operates commuter passenger service from Grand Central Terminal, via Southeast (change from electric to diesel power), to Wassaic.

[6][7] When the railroad was extended further, it provided a rail route for people and commerce northward to Albany, Boston, and towns in Vermont and Canada.

[7] On May 12, 1846, a new competitor received its charter to build a railroad alongside the Hudson River between New York City's lower Manhattan west side and Albany, backed mostly by wealthy Poughkeepsie manufacturers and merchants.

(It was completed to Albany on October 3, 1851, after a great amount of costly blasting, filling and tunneling the craggy eastern shore of the Hudson River.)

The Harlem Valley's directors started to worry that Boston would have a competitive advantage over New York City for the expanding "western trade.

[9] Among the company's founders was John Mason, a wealthy banker and president of Chemical Bank who was among the largest landowners in New York City.

They decided to build their railroad on the eastern side of Manhattan Island, convinced that it would never be able to compete with steamboat traffic on the Hudson River.

[16] The New York City Common Council passed an ordinance on December 27, 1854, to take effect in 18 months, barring the NY&H from using steam power south of 42nd Street, due to complaints by persons whose property abutted the right-of-way.

These trains ran through the Murray Hill Tunnel and turned west on 42nd before going north on Madison (northbound cars used Vanderbilt Avenue to 44th Street).