SAN FRANCISCO (Map, News) - As an effort starts to raise revenue for a new downtown transit terminal that would eventually link nine public-transportation systems under one roof, city officials say the trade-off would be to approve up to seven new high-rise towers in the neighborhood that would exceed the area’s current 550-foot limit.

Taxes on the new properties could pump as much as $420 million into the transit terminal project, designed to link a raft of bus and train routes by 2019, including a tunnel to the Caltrain station at Fourth and King streets.

On Wednesday, The City launched a public relations campaign to introduce the proposed zoning and neighborhood changes.

A lively downtown neighborhood with housing, offices and parks would be wrapped around the new 1,000-foot Transbay Terminal tower, according to city plans unveiled to the public Wednesday night.

A handful of the neighboring office towers would be allowed to reach 700 feet and 800 feet — considerably higher than the area’s current 550-foot limit. Decorative spires on the buildings could be allowed to pierce even higher into the sky.

The City’s tallest building is currently the Transamerica building at roughly 850 feet, according to David Alumbaugh, a senior city planner.

Alumbaugh said the proposed building height limits were carefully crafted to sculpt a dramatic skyline that will serve as a “hinge” between the high-rise residential Rincon Hill developments and the separate cluster of existing downtown buildings.

New towers allowed as a result of the plans could create up to 13 million square feet of office space, plans show.

“The terminal is fully funded,” city Economic Director Michael Cohen said. “But the [Caltrain] tunnel is like $2 billion, and it’s got a pretty big funding gap.”

Streets in the area would prioritize transit and walking. Cars would be banned from Mission Street between First and Fremont streets, and traffic lanes would be removed from Main, Spear, Fremont and Howard streets to widen sidewalks and create transit-vehicle lanes, according to the proposal.

Supervisor Chris Daly, who represents the area, said increased height and density can be a “plus” in certain areas if it comes with appropriate community and citywide benefits.

“Clearly, Transbay would deliver a world-class, multimodal transit center,” Daly said.

Shadows from the Transbay Tower would reach the Ferry Building in the winter months, according to a preliminary study. Morning shadows would reach Union Square in the summer months, St. Mary’s Square in the fall, and Portsmouth Square in late fall.

An environmental review of the proposal is under way with sign-off from various city bodies expected to begin late next year, according to city officials.

jupton@examiner.com