The Monson Railroad was a gauge

Rail gauge

Track gauge or rail gauge is the distance between the inner sides of the heads of the two load bearing rails that make up a single railway line. Sixty percent of the world's railways use a standard gauge of . Wider gauges are called broad gauge; smaller gauges, narrow gauge. Break-of-gauge refers...

 narrow gauge railroad which operated between Monson Junction on the Bangor and Aroostook Railroad

Bangor and Aroostook Railroad

The Bangor and Aroostook Railroad is a defunct United States railroad company, that brought rail service to Aroostook County, Maine. Brightly painted BAR box cars attracted national attention in the 1950s. First-generation diesel locomotives operated on BAR until they were museum pieces...

 and Monson, Maine

Monson, Maine

Monson is a town in Piscataquis County, Maine, United States. As of the 2000 census, the town had a population of 666. The town is located on Route 15 which is a somewhat major route north to the well known Moosehead Lake Region, to which Monson is sometimes considered a gateway...

. The primary purpose of this railroad was to serve several slate mines

Slate industry

The slate industry is the industry related to the extraction and processing of slate. Slate is either quarried from a slate quarry or reached by tunneling in a slate mine. Common uses for slate include as a roofing material, a flooring material, gravestones and memorial tablets, and for electrical...

 and finishing houses in Monson. Equipment was never modernized, and the railroad used antique stub switches

Railroad switch

A railroad switch, turnout or [set of] points is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction....

 and link-and-pin couplers

Coupling (railway)

A coupling is a mechanism for connecting rolling stock in a train. The design of the coupler is standard, and is almost as important as the railway gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.The equipment that connects the couplings to the...

 to the end of operations in 1943.
The slate underlying what became the town of Monson, Maine

Monson, Maine

Monson is a town in Piscataquis County, Maine, United States. As of the 2000 census, the town had a population of 666. The town is located on Route 15 which is a somewhat major route north to the well known Moosehead Lake Region, to which Monson is sometimes considered a gateway...

 had very low ionizable mineral content, and was well suited for manufacture of electric switchboard

Electric switchboard

An electric switchboard is a device that directs electricity from one source to another. It is an assembly of panels, each of which contains switches that allow electricity to be redirected. The U.S...

s.