After what they describe as an exhaustive study of the alternatives, Amtrak and the commuter railroads that use Pennsylvania Station in New York City say they have no choice but to take some property in Midtown Manhattan to make the station bigger.

The idea of expanding the subterranean station, the busiest transit hub in the country, to increase capacity has been kicked around for more than a decade. But community activists and some transit advocates have opposed it and demanded that Amtrak figure out how the existing Penn Station could accommodate more trains and travelers.

On Wednesday, officials of Amtrak, the Metropolitan Transportation Authority, New Jersey Transit and the other railroads gave their answer: There is no other way.

“We will need to reach beyond” the current boundaries of the station, which sits beneath Madison Square Garden, said Petra Messick, an Amtrak executive.

Here is what we know — and don’t know — about the project now.

How could Penn Station grow?

Despite a sustained decline in ridership on the region’s commuter railroads since the start of the pandemic in 2020, Amtrak and New Jersey Transit want to double the number of trains crossing the Hudson River during the morning and evening rushes. Construction has begun on a tunnel project, known as Gateway, that would add two tracks to the two that were built under the Hudson more than 110 years ago.

As part of that project, Amtrak has long had designs on a full block of Midtown just south of Penn Station. That block, like most of Midtown, is fully developed. It contains apartment buildings, restaurants and a Roman Catholic church that is more than 150 years old.