Fifteen stories below the bustling sidewalks of Park Avenue in midtown Manhattan, it's starting to look like a bona fide train station.

In the first MTA-guided press tour of its massive East Side Access project in two years, the progress is apparent and considerable: Ankle-deep mud and muck have been replaced by smooth, if dusty, concrete foundations and walls; jagged caverns are now perfectly cylindrical passages, waterproofed with bright yellow vinyl linings.

And flatbed train cars now regularly haul equipment and waste into and out of the Long Island Rail Road's future terminal on Manhattan's East Side -- much the same way that passenger trains will in about eight years.

"It was pretty raw two years ago. You saw rock. You saw everything. That's changed. We've built since [then] a lot. And we're going to continue to build," said MTA Capital Construction president Michael Horodniceanu, who led the tour. "Overall, I think we've made a lot of progress over the last two years. . . . It's really exciting to see how work progresses."

Still, there's a long way to go to complete the $10.2 billion megaproject, which aims to bring 160,000 LIRR customers each weekday to a new 350,000-square-foot concourse beneath Grand Central Terminal -- saving them up to 40 minutes a day in commuting time. The MTA calls it the largest transit infrastructure project underway in the United States.

About 1,800 contracted workers continue to toil around the clock on the project, which has several work sites both in Manhattan and in Queens. Eight years since heavy construction began, the project is about 60 percent completed, according to Horodniceanu. By early next year, the Metropolitan Transportation Authority expects to have committed about 80 percent of the project's budget.

advertisement | advertise on newsday

Critical to keeping the project on pace was the recent deal between the state and New York City to pay for the MTA's $29 billion capital program, which includes funding to complete East Side Access. That includes money to award a critical contract later this year that will finish transforming the underground caverns into a train station, including by building passenger platforms and laying track.

After numerous delays and cost overruns, Horodniceanu said he is confident that East Side Access is finally on track with a realistic budget and timeline. He said the project actually could be finished as early as 2020, but the MTA has given itself a two-year contingency cushion in case it hits another unforeseen obstacle.

"We have to stop looking in the past constantly, and look forward. We are now close to actually going forward and actually finishing it," Horodniceanu said. "I cannot redo the past. The only thing we need to do is learn from the past, to not actually make the same mistakes in the future. "