SAN FRANCISCO (KGO) -- Work on a regional connection for Bay Area commuters is quickly taking shape. With much of the construction on the Transbay Terminal completed underground, we're finally seeing it rise above street level.At First and Mission streets in San Francisco commuters are watching an icon rise, one that might actually make their trip into San Francisco easier someday. "You absolutely get a feel for what that experience is going to be when the transit center opens in late 2017," Dennis Turchon said.Turchon is senior project manager of the $1.1 billion new Transbay Terminal project.It is designed to be the Grand Central Station of the west, a hub for Bay Area transit.Regional bus lines will carry commuters to and from the city on the upper levels, while underground Caltrain and high speed rail will bring commuters up the Penisula."We've poured almost 100,000 cubic yards of concrete in the last year for the train box," Turchon said.Last August ABC7 News showed viewers where the trains would arrive underground. Now, that area is covered by concrete and from above you can see the rest of the station going up. When it's complete, it will be the size of two Transamerica Pyramid buildings laid side by side with a 5-acre public park on top. "It's basically a super-sized structure, you know it's like one of the world's heaviest, you know four story buildings," Sean McNeill Thorton Tomasetti said.Thorton Tomasetti is with structural engineering firm on the site and says building something this big in earthquake prone California is a challenge. "One of the principal goals of this structure was to provide a building that was going to be green tagged, you know after a large earthquake, essentially to be allowed open immediately for operation, you know with buses running on the second level," he said.Work in the blocks surrounding the center has ramped up too. "Right behind us is that new bus ramp that's going to come from the Bay Bridge into the transit center at the bus deck level," Thorton Tomasetti said.Those new ramps will be connected to the terminal by a suspension bridge over Howard Street, a gateway for those in a car or on a bus.Construction above ground is moving quickly and the structure is expected to cross over Fremont Street by the end of the summer.