The Detroit and Mackinac Railway , informally known as the "Turtle Line", was a railroad in the northeastern part of the Lower Peninsula of the U.S. state of Michigan. The railroad had its main offices and shops in Tawas City with its main line running from Bay City north to Cheboygan, and operated from 1894 to 1992. At the end of 1925 it incorporated 375 miles of road and 470 miles of track; that year the Turtle Line reported 81 million ton-miles of revenue freight and seven million passenger-miles. In 1967 it reported 124 million ton-miles on 224 miles of road. History The Detroit, Bay City & Alpena Railroad, was a narrow gauge short line operated from Bay City northward to the Lake Huron port of Alpena. The line was converted to in 1886 and was reorganized into the Detroit and Mackinac (D&M) on December 17, 1894. During the late 1890s and the first decade of the Twentieth Century, the timber resources of northeastern Michigan were fully utilized and the D&M expanded its trackage northward from Alpena to Cheboygan. The Bay City-Cheboygan main line prospered, and a stone passenger depot was constructed in Harrisville. The main constituent of the freight service offered by the D&M and its predecessor railroads was timber from what was then the vast forests of northeastern Michigan; the D&M built spurs and branch lines to the forested areas. Another branch line served the limestone quarries of Rogers City. In 1922, the railroad also had branch lines to Au Gres, Comins, Curran, Hillman, Lincoln, Prescott, and Rose City. In the 1940s, D&M had enough revenue to be a Class I railroad and it was one of the first such to eliminate steam locomotives in 1948. In March 1976, the Detroit & Mackinac acquired a combination of trackage and operating trackage rights from the remains of the bankrupt Penn Central that created an alternate main line from Bay City northward, through Gaylord and Cheboygan, to Mackinaw City. However, adverse economic conditions continued to affect railroad operations in the northeastern United States. The road was sold to the Lake State Railway in 1992, and ended its existence as an independent railroad. The Detroit & Mackinac called itself the "Turtle Line" and its logo symbol was "Mackinac Mac". The railroad bore the hostile backronym of "Defeated & Maltreated". Passenger service The D&M mainline from Bay City to Alpena offered sleeping