St. Clair river tunnel locomotive

Jim Lotz and Keith Mackenzie, Railways of Canada, Bison Books, 1988

Four of these 0-10-0 camelback locomotives, reportedly the largest of their time, were put in service in the St Clair tunnel soon after it opened in 1890. Six trains an hour, consisting of about 30 cars each, moved through the 6000 foot tunnel at three mph.
 A number of asphyxiations led to the replacement of steam with electric locomotives in 1908, an early use of Westinghouse's AC current system.