The mayor's proposed streetcar line was debated at a meeting in Brooklyn Tuesday night.

Hundreds showed up to hear the pros and cons of the BQX connector line, which would run between Astoria in Queens and Sunset Park in Brooklyn.

Opponents point to the $2.5 billion price tag and its potential to take away street and parking space.

But supporters say it's needed due to overcrowded subways and that it could be a boon for waterfront employment areas.

They also point to the lessons learned from other cities, which have or are planning to build streetcars.

"In Seattle, in Kansas City, there are models that are underway that you can pick and choose what makes the most sense for you among this amazing 16-mile potential alignment," said Rep. Earl Blumenauer of Oregon.

"We kind of look at streetcars and light rail as a technology whose time has come. And it's something else that needs to be part of the mix here in New York," said Tom Wright, president of the Regional Plan Association.

The city hopes to break ground by 2019 with hopes of getting service up and running by 2024.