The Urban Equivalent Of Letting Your Old Broken-Down Ford Decay In The Front Yard

Possible solutions to the problem of what to do with a 300-foot-long underground tunnel boring machine once you’re done with it include just simply burying it:

The 300-foot-long tunnel boring machines that will dig the tunnels for the Second Avenue subway, the extension of the no. 7 line, and the Long Island Rail Road connection beneath Grand Central Terminal could be one-hit wonders: They may be abandoned underground when their drilling work is completed.

Abandoning the machines, which cost between $15 million and $20 million apiece, may prove more efficient and cost-effective for project contractors than hauling them out through the holes they carve through soil and rock. If left underground, the machines would be turned away from the tunnels and then retired.

“We could leave it underground,” president of the Capital Construction Co. at the Metropolitan Transportation Authority, Mysore Nagaraja, said yesterday, referring to the tunnel boring machine that is scheduled to break ground on the Second Avenue subway project in 2008. The two tunnels that will run along Second Avenue, and perhaps the final resting place of the machine that creates them, will lie about 62 feet below ground, an MTA spokesman said.

“It’s a huge assembly. It’s not a simple machine, something you can hold. But how the contractor wants to use the machine is really up to him,” Mr. Nagaraja said. The contractor for the Second Avenue subway project will be announced today by MTA officials.

The spokesman for the city’s Department of Environmental Protection did not return calls yesterday concerning the environmental effects of leaving machinery underground permanently.