Long before the IND or BMT came into the picture—indeed literally at the dawn of subway building in New York—William Barclay Parsons was already engineering the encore to his "Rapid Transit Railroad" aka the Interborough Rapid Transit system, the first leg of our Subway system. Read more after the jump.
This map is from the "Railroad Gazette, 1907" posted online courtesy of Google Books.
Here the different routes are highlighted in colors that best interpret how the lines turned out today. In light gray are the old elevated lines, the already built IRT Subway and H&M Tubes.
Though narrower in scope compared to the Turner Plan and IND Second System, this does constitute an ambitious agenda given that Contract One was under construction and therefore built with these extensions in mind. (Contract One was finalized in 1897 and Contract Two which would extend the IRT north to Van Cortlandt Park and south to the LIRR's Atlantic Terminal was finalized in 1902). Missing from map is Brooklyn which saw an interesting and large series of "loops" (I put it in quotes because "loops" is used liberally by Parsons to describe both the small turnaround loops and massive circuitous routes).
Like the original IRT, this plans uses a lot of sharp curves and turnaround loops. There is also in significant density of parallel routes. This redundancy is often blamed on the competitive nature of the IRT and BRT/BMT, but every route was laid out by the government appointed committee without any previous bias (as far as I know) and the IRT had a monopoly on operation. The density of routes seems to me a desire on Parsons' part to eliminate as much surface transit as possible as well as good old fashioned Capacity Planning for future demand (which the current 7 train extension and 2nd Ave Subway seems to lack..ugh). Also you'll notice how lines in the Bronx, especially in the southwest, seem to stop dead before going any further north. They are in fact the intended connections to the existing railroad systems. Clifton Hood in his seminal work "722 Miles" described how the Rapid Transit Commission and later Public Service Commission had tried to persuade the existing private railroad companies (like the Pennsylvania RR, NY Central, B&O, et al) to add intracity transport to their intercity network. (I hope to cite examples of potential connections in future posts detailing the specific plans of Parsons' design).
One can also see in this map the shape of things to come. You can already see the beginnings of the Dual Contracts and IND systems. I hope to post images and Google Map mashups of the specific routes of this plan in the future. Enjoy.