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'''Original Rail Replacement''' - The original granite slab deck had two channels carved the entire length of the viaduct (discovered during the 1993 renovation) for longitudinal sleepers that provided continuous support of the rails. Typically, [http://www.buffalohistoryworks.com/ptracks/chapter4/strap-rail.gif strap rails] or [http://www.catskillarchive.com/rrextra/tksa08.Html bridge rails] were laid on longitudinal sleepers; these early [[Rail profile|rail types]] would have been replaced with flanged rails by 1840.
'''Original Rail Replacement''' - The original granite slab deck had two channels carved the entire length of the viaduct (discovered during the 1993 renovation) for longitudinal sleepers that provided continuous support of the rails. Typically, [http://www.buffalohistoryworks.com/ptracks/chapter4/strap-rail.gif strap rails] or [http://www.catskillarchive.com/rrextra/tksa08.Html bridge rails] were laid on longitudinal sleepers; these early [[Rail profile|rail types]] would have been replaced with flanged rails by 1840.


'''Longitudinal Sleeper Abandonment''' - It is unknown when the longitudinal sleepers were abandoned for traditional cross ties but it may have occurred when the original rails were replaced (around 1840) or when the line was double tracked in 1860. It is also unknown if longitudinal sleepers were used thoughout the railroad but [http://www.canton.org/junction/junction.htm pictures here] appear to show longitudinal sleepers at [[Canton Junction]] in 1871.
'''Longitudinal Sleeper Abandonment''' - The longitudinal sleepers may have been abandoned for traditional cross ties when the original rails were replaced around 1840. If not then, they would have been replaced when the line was double tracked in 1860. It is also unknown if longitudinal sleepers were used thoughout the railroad but [http://www.canton.org/junction/junction.htm pictures here] appear to show longitudinal sleepers at [[Canton Junction]] in 1871.


'''Ballast''' - Since the longitudinal channels held the sleepers in place the original tracks would have been [[Track ballast|non-ballasted]]. The viaduct tracks may have been ballasted when the longitudinal sleepers were abandoned for traditional [[cross ties]] unless the cross ties were fastened to them. If not, the viaduct tracks would have been ballasted in 1860 when the line was double tracked. Early photos of the top of the viaduct show dirt between the ties and tracks so this material may have been used before traditional gravel.
'''Ballast''' - Since the longitudinal channels held the sleepers in place the original tracks would have been [[Track ballast|non-ballasted]]. The viaduct tracks may have been ballasted when the longitudinal sleepers were abandoned for traditional [[cross ties]] unless the cross ties were fastened to them. If not, the viaduct tracks would have been ballasted when the line was double tracked in 1860. Early photos of the top of the viaduct show dirt between the ties and tracks so this material may have been used before traditional gravel.


*1860 - The 3'-8" high granite parapets were removed and replaced with a heavy wooden fence. A hard pine timber [[guard rail]] was bolted to the tops of the walls to retain the new [[Track ballast|ballast]] and a second track was added.
*1860 - The 3'-8" high granite parapets were removed and replaced with a heavy wooden fence. A hard pine timber [[guard rail]] was bolted to the tops of the walls to retain the new [[Track ballast|ballast]] and a second track was added.

Revision as of 01:04, 13 March 2009

Canton Viaduct
Canton Viaduct with Revere Copper Mill in the background
Coordinates42°09′32″N 71°09′14″W / 42.1589°N 71.1539°W / 42.1589; -71.1539
Carries

Present services:

Crosses
LocaleCanton, Massachusetts
Official nameCanton Viaduct

Nicknames:

  • "The Great Wall of Canton"
  • "Canton's Great Wall"
Maintained byAMTRAK
Heritage status
ID numberNA, bridge does not carry motor vehicles
Preceded byNone, the Canton Viaduct was the first and only bridge to span the Neponset Valley
Followed byNA, bridge still in active mainline use
Characteristics
DesignConsidered a "Multiple Arch" bridge but it is more accurately described as a Double Blind Arcade Viaduct.
Material
Total length615' built on a 1 degree curve which if extended would form a circle with a 42 mile circumference
WidthVaries:
  • 26'-28' at foundation
  • 24' at the base (above foundation)
  • 22' under deck, narrower than the base due to the 1":48" battre
  • 30' at top, wider due to the cantilevered, precast, prestressed concrete deck
HeightVaries:
  • 4' at southwest end (above ground)
  • 60' at northeast end (above water)
Longest span26' (original semi-circular vehicle arch)
No. of spans50 total:
Piers in water7
Load limit
Clearance aboveNA, no structures underneath the bridge
Clearance belowVaries:
History
Designer
Construction startThe Foundation Stone was laid on April 20, 1834 (a Sunday, perhaps for Masonic Builders' rites ceremony), symbolizing the first stone to be placed in the structure, however the 'construction phase' started prior with surveying, excavating, mobilization, site preparation, etc. Construction of the wing wall abutments is assumed to have been completed prior to the Foundation Stone being laid. The Cornerstone was originally set in the western end of the parapet as the structure neared completion. The actual foundation stone has never been located but should be in the northeast corner according to Masonic tradition and may contain an inscription and/or a time capsule.
Construction endJuly 28, 1835, but it may have been completed prior to the Opening date from various accounts of horse-drawn cars passing over it starting in June. The Canton Viaduct is assumed to have been 'substantially complete' in June and 'finally complete' in July.
Opened"Tuesday, July 28, 1835 saw the first regular passage over the viaduct", as reported by the Boston Advertiser, however The History Of Providence County, Rhode Island states, "On the 11th of June (1835) the road was opened for traffic". There is confusion over "regular passage", which is assumed to be steam locomotives and "opened for traffic", which could mean horse drawn cars. Perhaps the structure was not considered "finally complete" until "regular passage" was established between Boston, Massachusetts and Providence, Rhode Island via steam power. "Irregular passage" may have existed prior in the form of horse drawn cars, semi-functioning or late delivered steam locomotives.
Statistics
Daily trafficAnnual Average Daily Traffic:

History

Canton Viaduct is a stone viaduct erected in 1835 by the Boston and Providence Railroad Corporation (incorporated in 1831), one of the first New England railroads, designed by Army Captain William Gibbs McNeill and Army Major George Washington Whistler and built by Dodd & Baldwin. The two major groups of men who built the Canton Viaduct were the Scottish (Freemasons) stone cutters and masons and the Irish who laid the rough stone and built the gravel roadbed. Each facing stone has a Mason's mark to identify who cut the stone. Without Joseph Warren Revere, owner of the Revere Copper Company and a Director of the Boston and Providence Railroad Corporation the Canton Viaduct would not have been built. There were clearly better routes through other towns for the location of the railroad line from Boston, Massachusetts to Providence, Rhode Island. However, building the railroad through Canton placed the line close to his mill, where a spur shown here connected the mill to Canton Junction and undoubtedly gave a boost to his copper business. Tsar Nicholas I of Russia sent workmen to create technical drawings of the Canton Viaduct in order to build two duplicate bridges on the Moscow–Saint Petersburg Railway.

Design & construction

A partial isometric elevation of the Canton Viaduct with the deck removed showing its continuous parallel walls and hollow spaces between the buttresses

The bridge resembles a giant, rusticated stone wall supporting a train deck about 60 feet (18 m)[1] above the Canton River, a tributary of the Neponset River. The river passes through six semi-circular arches in the bridge, coming to a waterfall about 50 feet further downstream. The coping is supported by 42 segmental arches (21 on each side) that join the tops of 22 buttresses visible on the exterior of the structure. The buttresses are more accurately described as piers because they pass through the entire structure and are tied to the walls externally and internally rather than being solely external supports. The structure is actually hollow, composed of two parallel (longitudinal) walls each five feet thick with a five foot gap between them. See Construction Specifications for more detail. The structure is often identified as a "multiple arch" bridge based on its appearance. However, bridges are technically classified by their support method, so it is more accurately described as a Double Blind Arcade viaduct because the walls provide the main support (59%) for the deck, with the the arches providing the remaining 41%. The Canton Viaduct is the only known use of a structural Blind Arcade viaduct ever built in the United States.

The Canton Viaduct contains 14,483 cubic feet (15,800 perches) of granite, which weighs approximately 66,000,000 pounds (33,000 short tons). It is unknown if these values for the amount of material includes the foundation, piers, deck, parapet walls and wing wall abutments or if the vehicle and river arch openings were subtracted. This figure does not include the weight of the railroad tracks, ballast, iron railings, catenary poles or the new cantilevered, precast, prestressed concrete deck which is much heavier than the original granite slab deck due to its increased thickness and width.

The Canton Viaduct cost US$93,000 to build in 1835, which equates to $2.4 million in 2009 dollars. The construction took 15 months, 8 days from laying of the Foundation Stone to the official opening date.

The majority of the viaduct is over land (71%) while 29% is in the river. In addition to the six arches for the river, one large arch was provided in the original construction for Neponset Street. In 1786 the way leading from the Stone Factory Village to Washington Street under the viaduct (Neponset St.) was called Billings Lane, after William Billings II. In 1790 Billings Lane became known as "Ye Road from Ye Schoolhouse on Taunton Road to Ye Old Forge"; it is not certain when the name changed to Neponset Street.[2]

Renovations & repairs

Original Rail Replacement - The original granite slab deck had two channels carved the entire length of the viaduct (discovered during the 1993 renovation) for longitudinal sleepers that provided continuous support of the rails. Typically, strap rails or bridge rails were laid on longitudinal sleepers; these early rail types would have been replaced with flanged rails by 1840.

Longitudinal Sleeper Abandonment - The longitudinal sleepers may have been abandoned for traditional cross ties when the original rails were replaced around 1840. If not then, they would have been replaced when the line was double tracked in 1860. It is also unknown if longitudinal sleepers were used thoughout the railroad but pictures here appear to show longitudinal sleepers at Canton Junction in 1871.

Ballast - Since the longitudinal channels held the sleepers in place the original tracks would have been non-ballasted. The viaduct tracks may have been ballasted when the longitudinal sleepers were abandoned for traditional cross ties unless the cross ties were fastened to them. If not, the viaduct tracks would have been ballasted when the line was double tracked in 1860. Early photos of the top of the viaduct show dirt between the ties and tracks so this material may have been used before traditional gravel.

  • 1860 - The 3'-8" high granite parapets were removed and replaced with a heavy wooden fence. A hard pine timber guard rail was bolted to the tops of the walls to retain the new ballast and a second track was added.
  • 1880 - The wooden fence was removed and replaced with an iron fence and railings from the Edgemoor Iron Company.
  • 1887 - Safety tracks are placed on the viaduct on April 15. Safety tracks are installed to prevent trains from falling off the side of a bridge when derailed.
  • 1909 - A segmental arch stone dropped out of place from the fourth arch east of the original vehicle arch; stonemasons began repairing it on Sunday, December 19. An article titled, "More Trouble with the Viaduct at Canton Junction" in the December 24 edition of the Canton Journal describes this as the second arch to have given way. It is unknown if this "second arch" was a deck arch, vehicle arch or river arch, however the third river arch northeast end was repaired that same year.
  • 1910 - 42 concrete arches (21 on each side) were added under each segmental granite deck arch. The roadbed was widened by adding cantilevering off of the main structure.
  • 1952 - A second (concrete) segmental vehicle arch was cut next to the original granite semi-circular vehicle arch.
  • 1993 - The Massachusetts Bay Transportation Authority rehabilitated the bridge for Amtrak's high-speed Acela Express train service. The main objectives were to widen and strengthen the bridge with a new cantilevered, precast, prestressed concrete deck, replace the concrete arches added under each segmental deck arch, and perform electrification. During this renovation a series of parallel granite retaining walls were discovered at each end of the viaduct, presumably to absorb ground pressure as trains exited the bridge; a photo from 1871[3] may have captured one of these walls.

Recognition

The bridge was listed on the National Register of Historic Places in 1984.[4] It has been designated a National Historic Civil Engineering Landmark by the American Society of Civil Engineers. The Canton Viaduct will celebrate its 175th anniversary (Demisemiseptcentennial or Quartoseptcentennial) on July 28, 2010.




Footnotes

  1. ^ a b American Society of Civil Engineers article - Rebuilding History
  2. ^ Canton Historical Society: Old Canton Roads and Ways
  3. ^ Canton Historical Society: Canton Junction
  4. ^ "National Register Information System". National Register of Historic Places. National Park Service. 2008-04-15.

General references

Retrieved from "https://en.wikipedia.org/w/index.php?title=Canton_Viaduct&oldid=276877376"