emergency exits from stations with only a single headhouse. A pair of curved staircases were built from the western ends of the platform; they joined to form a straight staircase above the arch of the tunnel. The exit stairs were completed on September 6, 1904, with a small building in State Street covering them completed on October 10. A three-story headhouse, measuring , was built over Atlantic Chambers. The ground floor contained the main entrance and exit for the station. The second floor (of nearly identical plan) served a footbridge to the fare mezzanine of State Street station, while the third floor was a machine room for the elevators. The headhouse was designed by Charles Brigham, who had previously designed the Scollay Square and Adams Square headhouses for the Tremont Street Subway. Shafts leading to the headhouse served as the primarily ventilation for the Boston end of the tunnel. Each platform was served with two elevators, which rose to the ground floor and more to the footbridge level. Because the elevators needed to serve the separated platforms and the narrower headhouse, they were built with an angled section with approximately of vertical travel. The elevators were about apart on the platforms and apart at both headhouse levels; as late as the 1940s, the elevators were unique among subway stations. The BTC and BERy agreed in November 1903 to include the footbridge. However, the two could not agree on who should pay for the elevators: the BERy maintained they were a fundamental part of the station infrastructure and thus the responsibility of the BTC, while the BTC considered them an operational item and thus the domain of the BERy. In March 1904, they reached an agreement to allow construction of the elevators and headhouse (so as not to delay the station) while deferring the cost question. (The matter was not settled until a Massachusetts Supreme Judicial Court ruling in 1913.) The BTC awarded the contract for the headhouse on August 15, 1904, with completion scheduled for December 15; however, manufacture of the steel components was severely delayed. The East Boston Tunnel opened on December 30, 1904, serving streetcars which ran between Court Street downtown and Maverick portal in East Boston, where they joined existing surface lines. The only intermediate stop was at Devonshire; Atlantic Avenue station was not yet complete. Most of the headhouse except for some detail work was completed