Thursday, June 1, 2017

CP/DL&W Viaduct over Tunkannock Creek at Nicholson, PA

(Bridge Hunter, Historic BridgesSatellite (95 photos))

This is the photo that motivated me to write this post. DL&W was the Delaware, Lackawanna and Western Railroad and was the owner in 1928. As far as I can determine, the ownership linage was CP/NS/Erie Lackawanna/DL&W.

HAER PA,66-NICH,1--2

 GENERAL ELEVATION VIEW, LOOKING NORTHWEST - Erie-Lackawanna Railroad, Tunkhannock Viaduct, Nicholson, Wyoming County, PA


Circa 1920 photo from Bridge Hunter
"Measuring 2,375 feet (724 m) long and towering 240 feet (73.15 m) when measured from the creek bed (300 feet (91.44 m) from bedrock), it was the largest concrete structure in the world when completed in 1915" [Wikipedia]
When the Lackawanna Railroad's 39.6-mile Clarks Summit-Halstead Cutoff in northeastern Pennsylvania was dedicated on Saturday, November 6, 1915, the 2,375-foot-long, 240-foot-high Tunkhannock Viaduct stood at its west end. The total excavation for the cutoff had amounted to 13,318,000 cubic yards, more than half of that rock; into its substructures had gone 800,000 cubic yards of concrete. The Tunkhannock alone had required 1140 tons of steel, and 167,000 cubic yards of concrete containing 89,000 barrels or 1,093 carloads of cement. More than 50 years after its building, the Tunkhannock Viaduct still merits the title of largest concrete bridge in America, if not the world. [HAER]
"Concrete had not really been in use for bridge building all that long (mainly starting around 1900 [with the introduction of steel rods for reinforcement]), when this bridge was built in 1915." [HistoricBridges] And yet the concrete has remained good for over a century. In contrast, Historic Bridges reports that the concrete railings added in 1940 are already deteriorating.

The economic engine that made this cutoff possible was Anthracite coal in the Lackawanna Valley.
The clean, hot-burning fuel was perfect for running machines and building empires in the steam-dominated era. In fact, there was so much coal in the region that it could sustain 80% of the world’s fuel demands, ranging from heating to transportation, without the aid of any other source. 
Another revolutionary feature of the bridge was that it was designed to be 34 feet wide, allowing for north and south bound trains to pass simultaneously. This replaced the need to switch track connections in order to cross. That feature, coupled with reducing travel by 3.6 miles and eliminating 600 feet of unnecessary elevation, saved twenty minutes on the average passenger one-way train trip and an hour for freight deliveries to New York State.
The Nicholson Bridge was a part of the larger Clarks Summit-Hallstead Cutoff construction project devised by Henry Truesdale, who was looking for a way to shorten and straighten the railroad from Scranton to Binghamton, New York. Along with the Nicholson Bridge, a smaller replica, still huge by modern standards, was built nine miles north in the town of Kingsley, PA. This bridge is referred to as the Martin’s Creek Bridge, after the waterway over which it sits. Besides the two massive bridges, a 3,630-foot tunnel called the Nicholson Cutoff was built two rail miles south of Nicholson. The entire project was estimated to cost approximately $12,000 000, with the Nicholson Bridge itself accounting for $1,750,000. 
[PAbook2]

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