This is over simplified, but, at one time the West Side and Yonkers Commuter Railway ran from the terminus of the 9th Avenue El in front of the Polo Grounds at 155th Street on the east side of Manhattan, across the Harlem River Bridge, and followed the Putnam Mainline north from Sedgwick Ave into Van Cortland Park where it branched off onto the three mile long Getty Square Branch where it made 3 stops in Yonkers before terminating in Getty Square. The entire trip covered approximately 9 miles. The line was truncated and no longer crossed the swing bridge into Manhattan in 1916. The bridge was given over to the IRT. A terminal station was built at Sedgwick Ave where there was also a small steam locomotive servicing facility with a turntable serving the Put which now included the Yonkers branch. From the Sedgwick Terminal to Getty Square was 7.77 miles. These 2-4-4T would be filled with enough water and coal at Sedgwick to easily make the 15.5 mile round trip.
These were the 2-4-4T Brooks Locomotives Melgar mentioned above.
Looking from Manhattan across the swing bridge to Sedgwick.
Looking from Sedgwick Ave above the turntable. Swing bridge would be to the left.
Walkway coming off swing bridge. Stairs down to the Hudson Division trains.
Turntable and Engine House in the back left.
This aerial photo was taken sometime between 1933 and 1936.