in 1906 a small tunnel system opened under the downtown. the streets were crowded with horse-wagons. the tunnels were meant to carry things inside with no horses. coal and "ashes" (burnt coal) were always part of the business. most tunnels were wide and tall. the walls were made of concrete about thick. the tracks were "gauge" (the distance between the rails) and an electric "trolley" wire was mounted on the ceiling. two axle electric motor locomotives used electricity from the trolley wires. they pulled small freight cars.