SHoP ARCHITECTS Expands the existing site with a lightweight concrete structure that is meant to evoke the old Penn Station and seeks to make the station a social meeting spot. “When’s the last time you heard someone say, ‘Let’s meet for a drink at Penn Station?'” asked Vishaan Chakrabarti, a principal. “People say that about Grand Central all the time.”

SKIDMORE, OWINGS & MERRILL Moves Madison Square Garden off site and expands the station to four city blocks from two. Above ground: green space four times the size of Bryant Park; housing twice the size of Tudor City; more offices than Rockefeller Center; and more cultural spaces than Lincoln Center. “We saw Madison Square Garden as a sideshow,” said Roger Duffy, a design partner. “The primary purpose of the site is for the public and transportation.”

DILLER SCOFIDIO & RENFRO Moves Madison Square Garden across Eighth Avenue next to the James A. Farley Post Office building; Penn Station becomes a multilevel public space with amenities like a spa and a theater. “We’re making waiting a kind of virtue,” said Elizabeth Diller, a principal of the firm. “In New York, we’re always late and we think of waiting as a waste. How could you turn that into a positive attribute and actually come there early and spend more time?”

H3 HARDY COLLABORATION ARCHITECTURE Moves the entire complex to the West Side waterfront at 34th Street, creates an elevated bike and pedestrian promenade and turns Pier 76 into a new 16-acre park. “It’s an opportunity to do more than just fix things,” Hugh Hardy, a founding partner, said.