Complex sentence: Although chartered as early as 1866, active steps to finance construction of the railroad and tunnel came only in the autumn of 1870, and actual construction begun May 1,1871, and on July 24,1873, the first train passed through the tunnel.
Split into simpler sentences: Although chartered as early as 1866, active steps to finance construction of the railroad and tunnel came only in the autumn of 1870, and actual construction begun May 1,1871. On July 24,1873, the first train passed through the tunnel.