Under current proposals, Madison Square Garden would be relocated in the Annex of the Farley Post Office at the Ninth Avenue end of the building, and a new Penn Station - actually now called Moynihan Station East - would be built on the site of the existing Madison Square Garden, albeit under what could be two 90-story office towers. And over at Farley, Moynihan West would emerge, albeit hemmed in a bit by a new Madison Square Garden.

Both the risks and the advantages of this proposal are pretty clear. If everything goes well, commuters, long-distance travelers and the public in general will get a greatly enlarged, more functional and more appealing new Central Train Station, consisting of two parts, each of which could look and function better than at present. It would have spacious sun-filled concourses, ticketing services shared by the four agencies (NJ TRANSIT, Long Island Rail Road, Amtrak and New York City Transit), flexibility in platform assignments, up-to-the-minute train information in convenient locations, more numerous and visible entrances, as well as better platform access and other functionalities.

But if attention is not paid, a less appealing scenario could emerge in a decade, when construction is set to be finished. New York City could emerge with a new train station, but one that didn't look or work much better than today's station. The two towers above Moynihan East could - though not necessarily - limit the potential of a light-filled train hall and require enormous footings running through the stations down to the platforms. They could also make construction much more complicated, increasing the likelihood of disruptions in train service. (Construction at Atlantic Avenue in Brooklyn is a recent reminder of how disruptive construction above a station can be.) The station operations could continue to be managed by four separate agencies that refuse to cooperate. Over across Eighth Avenue, Moynihan West could emerge as the world's most beautiful arena, with a mere afterthought of a train station next to it.

Another potential liability is that, with what will probably be a set amount of funding contributed by the developer (though that amount has not yet been determined), taxpayers could be left with an enormous tab if the costs of the project skyrocket. In general, the risk on both sides of Eighth Avenue, and indeed in the Far West Side as a whole, is that private spaces and functions will crowd out public ones. This does not have to happen.

Preliminary plans for the station already seem to be going in the right direction - developers and the City are actively considering transferring development rights from Moynihan East to nearby sites, and they seem to be designing the station so it's spacious and passenger-friendly - but those plans could still change. What's important is that in the next few months and years, when the most important planning and design decisions are made, the public interest be heard - and placed ahead of the private interests of the developer and Madison Square Garden. Sure, they ought to benefit from the project, but not at the expense of New York's commuters.

For a longer look at the risk and rewards associated with the new Moynihan Station, see the recent report "A Regional Rail Center: Moynihan East and West," at www.rpa.org.

- Juliette Michaelson, Senior Planner, RPA