Question: Fabyan House was constructed by Sylvester Marsh who also built a railway which is technically what?

Context paragraphs:
Dungeness River Bridge: The Dungeness River Bridge is the centerpiece of Railroad Bridge Park near the town of Sequim, Washington.  It crosses the Dungeness River.  The bridge was first constructed by the Seattle, Port Angeles, and Western Railway, a subsidiary of the Chicago, Milwaukee, St. Paul and Pacific Railroad (also known as the Milwaukee Road) in 1916.  Because of the ready availability of timber, the bridge was built of wood.  This first bridge was replaced in 1930.  The new bridge was also built of timber, and like its predecessor, is a through Howe truss 156 feet long and 22 feet high.  Two wooden trestles are on the east and west approaches.

Grand Canyon Depot: Grand Canyon Depot, also known as Grand Canyon Railroad Station, was constructed in 1909-10 for the Atchison, Topeka and Santa Fe Railway at the South Rim of the Grand Canyon, in what is now Grand Canyon National Park.  It is one of three remaining railroad depots in the United States built with logs as the primary structure material.  The station is within 100 m of the rim of the canyon, opposite the El Tovar Hotel, also built by the railroad.  The depot is designated a National Historic Landmark.

Middlewich Manor: Middlewich Manor is a former manor house in Middlewich, Cheshire, England.  It was originally constructed in brick in about 1800, and it was encased in ashlar in about 1840, when the porch was also built The bay windows were added in the 1870s.  As of 2011, it is a residential care home.  The house is constructed in yellow ashlar and is in two storeys.  On its entrance front is a porch supported by four fluted Ionic columns.  Along the top of the porch is a frieze and a cornice.  On each side of the porch are two-storey canted bay windows.  Between the storeys is a band of Greek keys.  A parapet runs along the top of the house, behind which is a low-pitched roof.  On the garden front there are sash windows and a canted two-storey bay window to the right, and a wing with a stone oriel window and a pyramidal slated roof to the left.  There is more decoration with bands of Greek keys on this front.  The house is recorded in the National Heritage List for England as a designated Grade II listed building.

James S. Thompson House: The James S. Thompson House is a historical home located just outside New Boston, in Mercer County, Illinois.  The two story brick Italianate house was completed in 1862, built by James S. Thompson, a successful local businessman.  The property includes several outbuildings constructed at the same time as the house, including a wash house, wood storage house, and a privy, all made of brick.  A wooden barn and wooden children's playhouse were also built by 1862.

Van Ornam &amp; Murdock Block: Van Ornam & Murdock Block, also known as Lee House Block, is a historic commercial block located at Port Henry in Essex County, New York.  The block consists of four attached structures in the Italianate style built between 1874 and about 1880.  It is the focal point of the Port Henry business district.  The Van Ornam Block was built in 1874 and is a 3 ⁄ -story brick building with an ornately bracketed wood cornice.  The 4-story Lee House Hotel was also built in 1874 and is a 4-story brick structure.  The next building was built about 1880 and is a 2-story wood-frame building with a stamped metal facade.  The Harlan building is last on the block and it was also built about 1880.  It is a 2-story, flat-roofed brick structure.

Sylvester Marsh: Sylvester Marsh (September 30, 1803, Campton, New Hampshire – December 30, 1884, Concord, New Hampshire) was the United States engineer who designed and built the Mount Washington Cog Railway.

Motala Verkstad: AB Motala Verkstad is one of the oldest engineering companies in Sweden.  The company was founded in 1822 during the construction of Göta Canal.  Motala Verkstad has also built about 400 ships, 800 bridges (e.g. Västerbron, Skeppsholmsbron, Bergsnäsbron and the Ahvaz Bridge in Iran), railway equipment, 1300 locomotives.  The 118-meter-tall towers of Uppsala Cathedral were also built by Motala Verkstad.  During the 1970s the company was the world's largest exporter of kitchen sinks and during the 1980s they built landing gear for Swedish-built aircraft.  Today the company employs about 180 people.

Mount Pleasant House (New Hampshire): Mount Pleasant House was a grand hotel in the White Mountains of New Hampshire, in the area of Bretton Woods.  It was built in 1875 and opened in 1876.  Mount Pleasant House was one of three grand hotels in the area at the time during the early stages of an era of epic hotel building and more came soon after.  The other early grand hotels in Bretton Woods were White Mountain House and Fabyan House.

Mount Washington Cog Railway: The Mount Washington Cog Railway is the world's first mountain-climbing cog railway (rack-and-pinion railway).  The railway is still in operation, climbing Mount Washington in New Hampshire, USA.  It uses a Marsh rack system and one or two steam locomotives and six biodiesel powered locomotives to carry tourists to the top of the mountain.  Its track is built to gauge, which is technically a narrow gauge, as it is a ⁄ -inch (12.7 mm) less than .

Fabyan House: Fabyan House was a grand hotel in the White Mountains of New Hampshire, constructed by Sylvester Marsh who also built the Mount Washington Cog Railway.  The hotel burned during construction in 1868 and was rebuilt in 1872.  The 500-person hotel offered views of Mount Washington.  Offerings included fine dining, game rooms, parlors, and outdoor recreation.  A fire destroyed it in 1951.

Supporting paragraphs: Fabyan House Mount Washington Cog Railway
Answer: narrow gauge