Supplementing the First Avenue Subway (Route #1) and—one would assume—eliminating the need for a 3rd Avenue
Elevated, William Barclay Parsons designed a four-track subway to run under 3rd Avenue and Bowery. It's complicated set of tracks in the Bronx belie an ambition of the original transit planners; to have the city's subways operated by private railroad companies such as the New York Central Railroad and the Pennsylvania Railroad. In Midtown, there's also an interesting crosstown connection along 35th and 36th Streets.