For six months toward the end of 2011 and into 2012, my offices were located a short walk away from Grand Central, and every day, I took the subway through this den of people. The Grand Central subway station on the Lexington Avenue IRT is not particularly well designed. It’s crammed with subway riders, and due to the numerous staircases, there’s not a lot of platform space. Between the crowds slowly trudging up the stairs and people waiting for trains, it can often seem unsafely overcrowded.

It may get even worse. With Mayor Bloomberg attempting to fast-track a plan to rezone Midtown East, the area around Grand Central could see a rapid expansion in the amount of available office space. Already, sidewalks are too narrow and pedestrian areas very limited. But nothing is quite as bad as that Grand Central subway space, and if the city is to rezone the neighborhood, it must be careful attention to the needs of the area’s subway riders.

In a January Community Board 5 meeting, the city presented its latest plans for Midtown East, and as the DNA Info write-up noted, these plans include a call for transit investment. Matthew Katz reports:

City planners unveiled a revised East Midtown rezoning plan Tuesday that excludes a small segment of streets from the proposal and requires developers to chip in to a fund for transit improvements — before they can get a building permit…

Developers also would have to pay into the District Improvement Fund before getting building permits — instead of when they received the permits, city officials said. Critics said that’s still no guarantee the cash needed to improve the area would be raised, or that enough developers will even decide to bite. “We don’t know when development is going to occur and we need these improvements now,” [CB 5 Board member Raju] Mann said.

The improvements eyed include new escalators, stairs, passageways and space on platforms at some of Midtown’s most congested subway stations. The upgrades, estimated to cost between $340 million and $465 million, would focus on the train lines at Grand Central, the Fifth Avenue/53rd Street Station and Lexington Avenue/53rd Street Station.

Full plans for these stations haven’t been released, but we do know, for instance, that the MTA wants to reconfigure how people use Grand Central. As an example, the MTA sees transfer times of about 125 seconds for those traveling between the 7 line and the Lexington Ave. trains when that time should be closer to 45 seconds. More stairs and a wider mezzanine at Grand Central are on the agenda.

But what happens if the MTA doesn’t see these changes realized? That’s the headline of the day as officials told CB5 members back in October that if the re-zoning goes through without transit improvements, the MTA may have to consider temporary station closures during crush load times. Similar practices are at play throughout the world. Essentially, as The Post’s David Seifman noted, the MTA would consider closing some entrances at certain hours of the day to better control for people flow.

The MTA made clear that this is a less-than-ideal long-term solution. “There is zero risk that we will have to start closing entrances tomorrow or anything like that,” agency spokesman Adam Lisberg said The Post. Still, the MTA would need political support and a significant monetary investment to see these changes realized.

While the funds needed are likely to be included in one of the next five-year capital plans, it is an open question of how long the MTA can wait. Council member Dan Garodnik said, “There are infrastructure needs that we have today — even putting aside adding four million square feet of new commercial development and 8,000 people who are anticipated coming into Grand Central for the first time.” Essentially, then, any rezoning must pay special attention to the transit needs. Not doing so could lead to calamitous overcrowding and very frustrated subway riders.