Sometime around late 1991, Senator Daniel Patrick Moynihan caught wind of a plan being studied by Amtrak and the U.S. Postal Service to expand Pennsylvania Station into the neighboring Farley Post Office. The two agencies envisioned an expanded rail station with a sense of grandeur, as Penn Station’s train platforms ran under the column-lined post office.

New York’s senior senator, a Manhattan native, was sold on the concept almost immediately; he placed the estimated $315 million project at the top of his agenda. From then until his death, in 2003, he became the project’s biggest advocate as he pieced together the support of local politicians, fought for funding in Congress, and brought in President Clinton for the push. Now, still just a concept, the plan bears his name.

More than any other major project in the city, the plan for Moynihan Station has been wholly immune to success, caught up in a shifting tangle of stakeholders. The plan has undergone a familiar, frustrating rhythm of fits and starts since the early 1990s, as any near-final agreement has proved to be a house of cards that collapses as plans change for any one actor.

There has been no shortage of optimistic statements throughout:

“There’s no stopping us now,” Moynihan said in 1995.

“We are definitely going to move forward,” New York State development czar Charles Gargano said in 1999. “Construction will start this year,” he said again in 2006.

“We are very close,” Governor Spitzer said this past February.

All predictions proved for naught, and now, with key stakeholder Madison Square Garden’s announcement last month that it would stay in place and renovate, the most recent iteration has lost much of its momentum. While the private developers on the project—Vornado Realty Trust and the Related Companies—and city and state officials still hold out hope that the Garden could be brought back to the table, many involved with discussions concede that such a move would be a reach.

Discussions continue—Garden executives met with the city and the state last week, according to two people briefed on the meetings—though many say it would be difficult to secure, or outline, sources for well over a billion dollars of public funding with the Garden officially withdrawn from the project.

Time and again, the tripping point has been Moynihan Station’s bloated size and reach, especially with respect to the countless government agencies involved, as the agendas, priorities and funding levels across the public sector do not stay stable long enough for anyone to piece the project together and start construction. The political cycles, with leadership changes in Congress, Albany and City Hall always on the horizon, have seemed to prove too short to accommodate a project of this size.

“It was one of those jigsaw puzzles with 1,000 pieces,” said Tony Bullock, Moynihan’s chief of staff in the final years of the senator’s career. “It was like someone took 30 or 40 pieces away so you could never finish it.”

To name a few of the stakeholders: the U.S. Postal Service, Amtrak, New Jersey Transit, the Metropolitan Transportation Authority, the Port Authority, the mayor’s office, the Empire State Development Corporation. Tack onto that some of the private actors—James Dolan of Madison Square Garden, Steven Roth of Vornado, Stephen Ross of Related—and the half-dozen members of Congress who have tried to secure funding for the plan, and it gets rather difficult to fit everyone in the same room, let alone reach a consensus on anything.

Mr. Spitzer was the latest to fall victim to this unstable coalition of agencies, as the Garden ultimately pulled out of the project just after he resigned. The governor had been desperately trying to save the project in his final weeks and cobble together, in the very least, an outline of where the public funding would come from in order to settle the uncertainty of the Garden.

Indeed, during the same mid-February trip to Washington on which he met with alleged prostitute Ashley Dupré, he had meetings on Capitol Hill about federal funding for Moynihan Station, according to multiple people familiar with the matter. A few weeks later, the Friday before The New York Times broke news of his prostitution troubles, one of Mr. Spitzer’s final meetings as governor was with Senator Charles Schumer about the station, among other topics.

If the Garden does stay put, thereby scuttling plans to move it to the Farley building and redo Penn Station, the stakeholders seem committed to some sort of scaled-back plan, perhaps one closer in scale to Moynihan’s original vision (the plan involving the Garden came in at an estimated $14 billion, including surrounding development).

In retrospect, had Mr. Spitzer and his development deputy, Patrick Foye, been able to pull together the plan in just over a year, the act would have defied the project’s entire sluggish history.

From the mid-’90’s onward, there were constant instances when, with all the project financing secured and the light at the end of the tunnel getting brighter, one of the key players backed out for one reason or another.

Congressional funding took years to come through, and the task for Senator Moynihan became far more challenging when the Democrats became the minority party in 1995. Senator Moynihan ultimately roped President Clinton into the project, and the president put money for the project directly in the federal budget.

All the while, the station ran into obstacles with the others involved. The Postal Service was reluctant to give up most of its building for a small amount of money; Amtrak lost its will as its budget tightened.

As President Clinton left office in late 2000, success actually seemed within grasp, with both the funding—which had then swelled to almost $800 million—and needed approvals in place. Still, construction didn’t start immediately, and then the attacks of Sept. 11, 2001, threw another wrench into the plan, as the Farley building was needed to make up for damaged postal facilities downtown.

One delay caused many, and the project expanded some—the state agreed to buy the Farley building and then opted to bring in a private developer to defray costs—which, in turn, took more time to coordinate.

Once again, in 2006, the finish line was in view. Just as the sun was setting on the Pataki administration, which was leading the coordination of the project, the state finalized all the needed funding, the environmental review, and other steps for moving forward. But again, progress proved elusive, as the bigger, grander prospect of moving the Garden to Farley and redoing Penn Station in a larger scheme captured legislators, including Assembly Speaker Sheldon Silver, who voted down a needed approval for the Farley project.

Advocates of the larger plan said that approval of the Pataki administration’s plan at that time would have made it harder to ultimately lure the Garden into Farley. But the move infuriated the Pataki administration, as Mr. Gargano, then the state’s development chief, said approval of the smaller plan did not preclude a move by the Garden.

“It was off the ground, it was getting off the ground. Everything was in place, and then it was killed by one negative vote by the speaker,” Mr. Gargano told The Observer. “You hear the excuse, ‘Well, we must build the larger project.’ What the hell does that mean?”

Now the larger dream that killed Mr. Gargano’s plan is looking near-dead, as the Garden, eager to get a better facility, failed to be convinced that the Farley deal would ever happen. The amount of federal funding being sought was a big reach, and it didn’t seem to help that Mr. Spitzer had an antagonistic relationship with a key backer, Senator Schumer, according to people familiar with the effort to secure funding. Since Mr. Spitzer left office, Mr. Schumer has become increasingly vocal in his support for the project.

Whatever becomes of the most recent chapter of the Moynihan Station saga, certainly no decisions are imminent.

Governor Paterson is considering putting the Port Authority of New York and New Jersey in charge of the whole project, given the agency’s background in construction and transportation and well-funded capital plan, according to people familiar with discussions.

The Empire State Development Corporation, the state agency currently coordinating the Moynihan Station effort, is without a clear leader, as Mr. Foye, the downstate chairman, announced his resignation last month, and Mr. Paterson has yet to install someone in his place.

Mayor Bloomberg has expressed continued support for the plan, but it is the state that sits in the driver’s seat.

Among both onlookers and many involved in the project, the concept of the larger plan that included a redo of Penn Station seems to have changed the way people view the smaller plan, which just involves the Farley building. A few years ago, the Farley plan was once referred to almost in messianic terms. It would allow for a new, grand Penn Station for the hundreds of thousands of commuters that pass through every day, people said at the time.

But today, officials are quick to note that it is but an expansion, one that connects only to the far western end of most—but not all—of the train platforms. And it would bring commuters using New Jersey Transit, which committed to anchor the building in 2005, only to Eighth Avenue, while the bulk of office jobs are east of Seventh Avenue.

“When Moynihan Station was just about putting a new train hall in the Farley building, it was important, but it wasn’t a higher priority than the No. 7 subway extension, the Javits expansion or development of the Hudson Yards,” said Tom Wright, executive director at the Regional Plan Association. With development possible on both sides of Eighth Avenue, “now there’s a real feeling that this is the most important project in the city,” he said.

It remains to be seen to what extent a renovation of Penn Station is possible with the Garden staying in place, as it is unclear how much political will there is to do so. The Farley component nearly approved in 2006 still has its more than $800 million in funding set aside, though costs have risen in construction projects everywhere since.

Whatever path Mr. Paterson ultimately chooses, it seems difficult to see any scenario where implementation is just around the corner, as, consistent with Moynihan Station’s history, decisions are not made easily.

“Its level of complication, amount of funds, emotion, everything, is 10 times a greater level than anything else that I’ve dealt with,” said David Childs, the Skidmore Owings & Merrill partner who designed the Farley building renovation. “You’ve got to get every single one of those players, plus money, to agree at the exact same second to do it, and that’s what’s hard to get.”

The defining nature of the Moynihan Station project up until now—its inability to get off the drawing boards—is tinged with irony, especially given its name. Senator Moynihan, his friends and associates say, was constantly focused on getting projects built and avoiding the never-ending preparations that often characterize large infrastructure projects. For those projects he was involved in, the senator badgered his staff with directives to get shovels in the ground, former staffers say.

“In an odd way, it is the proof of everything Moynihan tried to teach us,” William T. Cunningham, a former chief of staff for Moynihan, said of the project’s inability to proceed. “He taught us that things weren’t getting done; the city [and state and federal government] didn’t have the same energy and drive to get things done.

“He would appreciate the irony while ruing the outcome.”