 The new center is planned to eventually include an extension of Caltrain into the station from the current Caltrain Depot at 4th and King Streets in Mission Bay via tunnels which would also carry the Bay Area segment of the future California High-Speed Rail (CAHSR) and terminate at the station, as mandated by California voters in Proposition 1A, the ballot measure authorizing CAHSR construction.This extension would cost an additional $2-4 billion and is currently unfunded.The Transit Center currently has three levels plus a public rooftop park.