The West Shore Subdivision is a railroad line owned by CSX Transportation

CSX Transportation

CSX Transportation operates a Class I railroad in the United States known as the CSX Railroad. It is the main subsidiary of the CSX Corporation. The company is headquartered in Jacksonville, Florida, and owns approximately 21,000 route miles...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

. The line runs from Fairport, CP-359, west to North Chili, CP-382, along a former New York Central Railroad

New York Central Railroad

The New York Central Railroad , known simply as the New York Central in its publicity, was a railroad operating in the Northeastern United States...

 line. Both of its ends are at the Rochester Subdivision

Rochester Subdivision

The Rochester Subdivision is a railroad line owned by CSX Transportation in the U.S. state of New York. The line runs from Syracuse west to Buffalo along the former New York Central Railroad main line. At its east end, west of downtown Syracuse, the line becomes the Mohawk Subdivision...

; it provides a southern bypass of Rochester. Genesee Junction is located on the West Shore, where CSX interchanges with both the Livonia, Avon and Lakeville Railroad

Livonia, Avon and Lakeville Railroad

The Livonia, Avon and Lakeville Railroad is a short line railroad that operates in Livingston County and Monroe County in New York, United States...

 and the Rochester and Southern Railroad

Rochester and Southern Railroad

The Rochester and Southern Railroad , a subsidiary of Genesee & Wyoming Inc., is a class III shortline that runs from the city of Rochester in Monroe County to Silver Springs, NY. The RSR started in 1986, when the B&O sold off its Buffalo and Rochester branches...

.

Dispatchers often make the statement: Down The Shore After 4 due to Amtrak being in the City of Rochester then.
The entire line opened in 1884 as part of the New York, West Shore and Buffalo Railway.