Railway Commissioners denied the West End permission to run electric streetcars on Brattle Street. That November, a compromise was worked out where the West End would instead build on Mount Auburn Street (which had been considered in 1891); a parallel line on Concord Avenue and Huron Avenue (ending at Aberdeen Avenue and Mount Auburn Street) would be opened within eight months, and the Brattle Street horsecar tracks removed in the same time frame. The Mount Auburn line opened in April or May 1894, with the Concord/Huron line opening later in the year. A branch from Mount Auburn Street to Waverley Square in Belmont opened on October 1, 1898, despite Watertown's opposition earlier than year to widening Belmont Street. A branch to Belmont Center opened on June 30, 1906; it was replaced by buses in August 1928 and was never a trackless trolley route. On April 1, 1938, trackless trolleys replaced streetcars on the Harvard–Aberdeen Avenue line (72). In 1955 the Harvard–Arlington Heights line was converted from streetcars to diesel buses, but streetcars continued to provide short-turn service between Harvard and North Cambridge. Starting in 1957, trackless trolleys provided short-turn service from Harvard to Benton Square on the route to Waverley. The Harvard–Watertown Square (71), Harvard–Waverley (73), and Harvard–North Cambridge (82, renumbered 77A c. 1967) lines were all converted from streetcars to trackless trolleys on September 6, 1958. These four Harvard-based trackless trolley routes remained long after the rest of the bus system had converted to diesel and existed, in part, because of a desire to limit the number of diesel buses in the Harvard bus tunnel. Inside the portals, the tunnel splits into two one-way tunnels, upper and lower. The tunnel for eastbound-northbound vehicles is placed on top of the tunnel for southbound-westbound vehicles. The tunnels first opened for streetcars in 1912, and trolleybuses began using them in 1938. Streetcar service using the tunnel was abandoned in 1958. In a six-year project lasting from 1979 to 1985 (coinciding with the reconstruction of Harvard station during the Northwest Extension of the MBTA Red Line), the tunnel was closed for an extensive rebuilding, which included new platforms and a new northern portal ramp. (The preservation of these lines has also been attributed to the environmentalist movement of the 1970s.) In January 2005 most route 77A (Harvard–North Cambridge) service was eliminated; the only remaining trips were pull-ins and pull-outs to take 71 and