premise: Tremont Street Subway is incapable of being a tunnel.
hypothesis: The Tremont Street Subway in Boston 's MBTA Subway system is the oldest subway tunnel in North America and the third oldest worldwide to exclusively use electric traction ( after the City and South London Railway in 1890 , and the Budapest Metro 's Line 1 in 1896 ) , opening on September 1 , 1897 .