TUNNELLED SECTIONS FOR THE BUFFALO METRO

The article describes the design, layout and construction of the first mainly underground light-rail transit system being built in New York. Construction started in 1979 on an initial 6.4 mile section of the system which will employ steel-wheeled rail cars and an overhead traction power supply. The section under construction will follow the alignment of Main Street at ground level along a pedestrian mall and then continue in a reinforced concrete box tunnel structure constructed by cut-and-cover methods through soft ground to depths of 30-50 ft. For the remainder of the route the line will then run in rock tunnels at depths from 60-90 ft. Details are given of tunnel excavation methods used in which fullface tunnel boring machines have been used to cut the two 16 ft internal diameter running tunnels through the rock section. Other constructions in the rock section include a double crossover and a 496 ft long storage tunnel. (TRRL)