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 ws alternating current.
Note: The tower at North Kearsley was built about the same time, both by Federal Signal Co.
Source: [RSG] November, 1923 page 447-449.