Interlocking: Flint, MI - PM Belt & DUR Crossing

This interlocking was created about 1923 when the Pere Marquette railroad constructed their "Belt Line" on the east side of Flint. The Belt Line began at Atwood Junction (2 miles south of Flint) and reconnected with the old main line at McGrew Yard (about 4 miles north of Flint). This interlocking apparently known as Crego, as identified in a PM telegrapher labor agreement in 1927. It was staffed by the PM on all shifts. [PMTA][MPSC-1923]

This interlocking had a tower which controlled four derails and four signals, two of each on each road. Both the PM Belt and the DUR were single track at the time the crossing was built in 1923.

The tower had a 16-lever Federal Signal Company Type 341 d.c. electric interlocking machine with d.c. indication. The machine was provided with 8 spare levers for future extensions.

This tower had two floors, the first floor being divided into two rooms. One room contained a hot air heater and a work bench, while the motor generator, storage battery and relay cupboard were located in the other room. The second floor of the tower was the operating room.

The power plant consists of 60 cells of Electric Storage Battery Company's 120 a.h. "Ironclad" Type M-V-S-9 storage battery arranged in five cells to each tray. The batteries are trickle charged by a General Electric Co. motor generator set. The cable controlling the signals were installed on poles with junction boxes at the signals. All signals were electric lighted, the home and dwarf signals being controlled by transposition switches on the tower switchboard and the distant signals lighted by a low-voltage approach lighting scheme. The plant had an illuminated spotlight track diagram for all track sections. The energy for track circuits was alternating current.


The tower at North Kearsley was built about the same time, both by Federal Signal Co.

Source: [RSG] November, 1923 page 447-449.

Time Line

1922. The PM is planning installation of two interlocking plants at Flint on the new belt line of the PM which is being built around the city. One of these plants will be a 48-lever machine with 12 spare levers and 36 working levers. This plant will handle the functions at the crossing of the Flint belt line and the GT passenger line and another crossing at the Grand Trunk freight line, the two crossings being located 3,450 feet apart. The other plant at the crossing of the Flint belt line and the Detroit United Railway will use a 16-lever frame with 8 spare levers and 8 working levers. Both of these machines will be the all electric type furnished by the Federal Signal Company, Albany, NY and an Exide type battery furnished by the Electric Storage Battery Co, charged by the trickle charge arrangement, will be used at both plants. [RSG-1922-09]




The following sources are utilized in this website. [SOURCE-YEAR-MMDD-PG]:

  • [AAB| = All Aboard!, by Willis Dunbar, Eerdmans Publishing, Grand Rapids ©1969.
  • [AAN] = Alpena Argus newspaper.
  • [AARQJ] = American Association of Railroads Quiz Jr. pamphlet. © 1956
  • [AATHA] = Ann Arbor Railroad Technical and Historical Association newsletter "The Double A"
  • [AB] = Information provided at Michigan History Conference from Andrew Bailey, Port Huron, MI

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