page_title: Canton Viaduct
section_title: Construction
hierarchical_section_title: Canton Viaduct / Design and construction / Construction
context_page_description: Canton Viaduct is a blind arcade cavity wall railroad viaduct built in 1834–35 in Canton, Massachusetts, for the Boston and Providence Railroad.
  At its completion, it was the longest and tallest railroad viaduct in the world; today, it is the last surviving viaduct of its kind. It has been in continuous service for 184 years; it now carries high-speed passenger and freight rail service.
  The Canton Viaduct's walls are similar to the ancient curtain wall of Rhodes with rusticated stone. It supports a train deck about 60 feet above the Canton River, the east branch of the Neponset River. The stream pool passes through six semi-circular portals in the viaduct, flowing to a waterfall about 50 feet downstream.
  The viaduct was the final link built for the B&P's then 41-mile mainline between Boston, Massachusetts; and Providence, Rhode Island. Today, the viaduct serves Amtrak's Northeast Corridor, as well as Massachusetts Bay Transportation Authority Providence/Stoughton Line commuter trains. It sits 0.3 miles south of Canton Junction, at milepost 213.74, reckoned from Pennsylvania Station in New York City, and at the MBTA's milepost 15.35, reckoned from South Station in Boston.
context_section_description: The Canton Viaduct cost $93,000 to build ($2,304,900 today). Construction took 15 months, 8 days from laying of the foundation stone on April 20, 1834, to completion on July 28, 1835.
  The first and last transverse walls (next to the wing wall abutments) are only 3 feet wide, all the other transverse walls are 5 feet, 6 inches wide.  The wing wall abutments are 25 feet wide where they meet the viaduct; they are curved and stepped and were excavated by William Otis using his first steam shovel.  From the top of the wing walls to midway down, the stones are of 2' wide; from midway down to the bottom of the wing walls the stones are 4' wide.
  The coping is supported by 42 segmental deck arches (21 on each side) that span the tops of 22 transverse walls beyond the longitudinal walls.  The longitudinal walls are five feet thick with a four-foot gap between them joined with occasional tie stones.  More construction details are available in the original specifications.  When the viaduct had a single set of tracks, the rails were placed directly over the longitudinal walls as the cavity's width is less than standard gauge.  When the viaduct was double tracked in 1860, the inside rails were placed directly over the longitudinal walls and the outside rails were supported by the deck arches.
  The viaduct was "substantially complete" in June 1835 from various accounts of horse-drawn cars passing over it during that time.  The viaduct was built before the advent of construction safety equipment such as hard hats and fall arrest devices.  Surprisingly, no deaths were recorded during the construction, but deaths have occurred at the viaduct since completion; mainly from people crossing it while trains passed in opposite directions.  Charlie, the old white horse who had hauled the empty railcars back to Sharon, Massachusetts (4 miles), was placed upon the flat car and hauled across the viaduct by the workers, thus becoming the first "passenger" to cross the structure.
  A June 6, 1835, article in the Providence Journal describes it.  As reported by the Boston Advertiser and the Providence Journal,  "Whistler" was the first engine to pass over the entire length of the road.  The engine was built by Robert Stephenson in 1833 in England and named by William Gibbs McNeill in honor of his brother-in-law George Washington Whistler.  The trip from Boston to Providence cost $2 one way.
  There are examples of Fibonacci numbers and golden ratios in the Canton Viaduct:
  The inscription on the back of the Dedication Stone is recessed into an elongated octagon.
  The original roadway portal was built through the eighth cavity from the south end and the concrete roadway portal was built through the thirteenth cavity from the north end.
  The rise of the original roadway portal is 8 rows and the rise of each deck arch is 3 rows.
  There are 5 voussoirs in each arch row (depth) of the original roadway portal and river portals.
  There are 21 deck arches on each side of the viaduct and 21 voussoirs in each deck arch.
  There are 21 cavities in the viaduct.
  There are 13 voussoirs in each river portal.
  There are 3 rows of stones in the Canton Viaduct monument, the bottom and middle rows have 8 stones each.
  Aside from seasonal vegetation control and occasional graffiti removal, the viaduct requires no regular maintenance other than periodic bridge inspections from Amtrak.
caption: A random sample of Canton Viaduct Mason's marks; there are thousands of stones in the structure and each has a symbol to identify who cut the stone.
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