Cambridge Seven originally intended to use red, yellow, green, and blue for the four lines. However, yellow proved unsuitable, since some patrons would have difficulty reading yellow text on a white background; orange was substituted, and yellow eventually was used for the MBTA bus service's visibility markings and signage. When sketching design concepts, Peter Chermayeff labeled the subway-surface light rail routes as the Green Line because they run adjacent to parts of the Emerald Necklace park system. The East Boston Tunnel became the Blue Line because it runs under Boston Harbor, and the Cambridge-Dorchester Tunnel became the Red Line because its northernmost terminus was then at Harvard University, whose school color is crimson. According to Chermayeff, the Main Line El "ended up being orange for no particular reason beyond color balance." The MBTA and transit historians later claimed that orange came from Orange Street, an early name for the street that ran southwards down the Boston Neck to connect the Shawmut Peninsula to the mainland, for what is now part of Washington Street.