Canton Viaduct

Canton Viaduct
A west side view of the Canton Viaduct looking south with the former Paul Revere Copper Rolling Mill in the background, April 1977
Coordinates	42°09′32″N 71°09′14″W / 42.15889°N 71.15389°W / 42.15889; -71.15389Coordinates: 42°09′32″N 71°09′14″W / 42.15889°N 71.15389°W / 42.15889; -71.15389
Carries	2 tracks (standard gauge) presently serving: Amtrak's Northeast Corridor (intercity passenger) MBTA's Providence/Stoughton Line (commuter) CSX's Boston Subdivision (freight)
Crosses	Canton River (at Mill Pond) Canton River Valley (Canton Dale) Neponset Street
Locale	Canton, Massachusetts
Other name(s)	The Great Wall of Canton Canton's Great Wall
Maintained by	Amtrak (owned by the Massachusetts Bay Transportation Authority (MBTA)
Heritage status	National Register of Historic Places (1984) National Historic Civil Engineering Landmark (1998)
Characteristics
Design	Blind arcade cavity wall
Material	Walls - Granite Deck - Reinforced concrete
Total length	615' (built on a one degree )
Width	26'-28' foundations 22'-24' walls; wider at the bottom than the top due to the 1":48" battre (sloped surface) on the exterior surface of walls 30' deck; wider due to the cantilevered, precast, prestressed concrete deck
Height	Varies due to valley contour, built with a stepped foundation. 4' above ground level at southern end 60' above river level 70' maximum height (from foundation to coping)
Longest span	2 at 28' (granite/concrete deck arches over the granite roadway portal)
No. of spans	71 total: 21 at 4' long (cavity ceiling slabs) 6 at 6' long (river portals) 1 at 18' long (concrete roadway portal added in 1953) 1 at 22' long (granite roadway portal) 40 at 24' long (granite/concrete deck arches) 2 at 28' long (granite/concrete deck arches over the granite roadway portal)
Piers in water	7 (15 on land)
Load limit	Unknown, currently carries Amtrak's 100-ton Acela Express up to 125 MPH
Clearance above	Approximately 21' from top of rails to contact wires of the catenary system
Clearance below	23' under the granite roadway portal 18' under the concrete roadway portal 6' under the six river portals
History
Designer	William Gibbs McNeill, Chief Engineer for the Boston & Providence Railroad (B&P)
Construction begin	April 20, 1834
Opened	July 28, 1835
Statistics
Daily traffic	Trains passing over = 106 / day (November 2004) Freight traffic not included. Motor vehicles passing under = 16,400 / day (2005 traffic study)
Canton Viaduct
U.S. National Register of Historic Places
Location	Neponset and Walpole Sts., Canton, Massachusetts
Built	1834
NRHP Reference #	84002870
Added to NRHP	September 20, 1984
Canton River Valley at the intersection of Neponset St. and Walpole St.

2 tracks (standard gauge) presently serving:

Varies due to valley contour, built with a stepped foundation.

71 total:

Canton Viaduct is a blind arcade cavity wall railroad viaduct built in 1834-35 in Canton, Massachusetts, for the Boston and Providence Railroad (B&P).

At its completion, it was the longest (615 feet) and tallest (70 feet) railroad viaduct in the world; today, it is the last surviving viaduct of its kind. It has been in continuous service for 181 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 (built about 400 BCE) with rusticated stone. It supports a train deck about 60 feet (18 m) above the Canton River, the east branch (tributary) 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 (MBTA) Providence/Stoughton Line commuter trains. It sits 0.3 miles (0.5 km) 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.