All stations are designed per BART standards and house many required BART support facilities within:
First, all stations have 700-ft long platforms to accommodate a typical 10-car BART train.
Second, station depth is driven by the tunnel alignment and the required space above the tunnel. The two downtown stations have entrance buildings adjacent to the tunnel to avoid needing disruptive cut-and-cover construction in the streets. Passengers enter these entrance buildings from the street level and take escalators, elevators, or stairs down to the platform levels.
Third, the primary entrance buildings for the downtown stations are a circular shape because it is structurally more efficient to construct than a rectangular shaped shaft. However, the secondary entrance building at Downtown San Jose is rectangular due to right-of-way constraints.