CITY HALL -- A subway will most likely never go to Staten Island.

Metropolitan Transportation Authority head Tom Prendergast explained to Borough President James Oddo this month that connecting Staten Island to Brooklyn through a rail tunnel would be particularly challenging.

"Even 90 years ago, funding constraints were a major consideration in the decision to not undertake a complex and at times, politically charged, project," Prendergast wrote to Oddo on Oct. 3.

Oddo wanted to know if the MTA had ever analyzed the proposal in the decades since the project was abandoned.

"Whenever we talk about Staten Island's transportation problems, someone inevitably brings up the start of the rail tunnel almost a century ago," Oddo said in a statement.

A CENTURY OF DREAMING

Plans for a subway link to Brooklyn were among reasons why Staten Islanders wanted to consolidate with the other four boroughs in 1898. A decade before that, the Baltimore & Ohio Railroad proposed a tunnel between Brooklyn and Staten Island but the the plan was never funded.

Such a connection to the Brooklyn-Manhattan Transit (or BMT) subway system was actually mapped as part of an expansion of additional lines through the Dual Contracts.

The idea was to extend the 4th Avenue BMT R line under the Narrows and connect it to what's now called the Staten Island Railway.

"While a shaft was sunk about 150 feet into the Narrows, a rail tunnel from Owl's Head Park to Staten Island never came to fruition," Prendergast wrote to Oddo.

He added that no formal or informal studies have been conducted since the state legislature created what is now known as MTA New York City Transit in 1953.

BUT WHAT IF?

Oddo said he also wanted to know what would happen "if the MTA suddenly became flush with the many billions of dollars needed for such a project."

"In the event that NYCT came across the funding to make this tunnel a reality," Prendergast wrote, "the hypothetical 'next steps' would be to start with some sort of high level needs/feasibility study to understand what the potential benefit for this would be, what sort of land use changes it would induce, what development would be required and what sort of routing and service options would be feasible."

The alternative analysis process would begin, followed by preliminary engineering and an environmental impact statement.

"Aside from the cost engineering constraints and finding sound ways of operating additional service alone 4th Avenue R in Brooklyn, carrying this out today would also prove to be extremely challenging on the Staten Island side," Prendergast wrote. "If we were able to connect 4th Av R service to Staten Island, the line would tie into the middle of SIR, requiring comprehensive track reconfigurations."

And if that's not enough, Prendergast added, "The introduction of R service into the SIR system would also have considerable scheduling impacts on the current SIR operation."

This timeline can vary, but Prendergast pointed to the long process for the Second Avenue Subway in Manhattan. Planning and environmental review began in 1995 and opening of the first phase is only expected later this year.

OTHER PROJECTS IN WORKS

Oddo said that Staten Island still has "other potentially transformative projects on the drawing board that are much more likely to occur" like the North Shore Bus Rapid Transit, increased fast ferry service and West Shore Light Rail.

The Staten Island subway will still be a distant dream for the mass transit-starved borough.

"I understand if such a project were viable there would be some who oppose it and some who strongly support it," Oddo said. "I couldn't say where I would stand because there is no realistic proposal."