Railroads aim to replace or revamp aging bridges

Posted Říjen 25th, 2011 by Billabongboardshortscloths

Heavy coal and grain trains, more frequent passenger-rail traffic, extreme temperatures, and rain, snow and ice are taking a toll on rail bridges. Decades of service are compromising their condition,we supply all kinds of polished tiles, as well. Many U.S. rail bridges are close to or more than a century old.

With bridges and trestles continuing to age and wear out, there’s a growing need to rebuild or replace many of them. So, railroads are pursuing projects designed to do just that.

Hundreds of bridges are monitored by Norfolk Southern Railway engineering department officials, who maintain an inventory that includes a description of each bridge. All bridges are inspected at least annually, condition is recorded and performed maintenance is logged. The Class I’s bridge program typically involves many projects performed simultaneously.The additions focus on key tag and impact socket combinations,

“Approximately 100 bridge projects in the rehab or construction phase are going on at all times on the system,” says NS Chief Engineer of Bridges and Structures Jim Carter.

Each year, NS tries to replace timber trestles,Save on Bedding and fittings, many of which are up to 70 years old. The trestles typically are replaced with ballast deck precast, prestressed concrete and box girders mounted on pipe pile filled and capped with concrete, says Carter.

Emerging technology could play a role in future bridge projects, such as a hybrid composite beam (HCB), he says. Comprising a carbon-fiber reinforced concrete arch encased with fiberglass, HCB is undergoing tests at the Transportation Technology Center Inc.Flossie was one of a group of four chickens in a RUBBER MATS .’s Facility for Accelerated Service Testing (FAST) track in Pueblo, Colo. The beams might begin entering the mainstream as an option for bridge work, but for now, NS has no plans to use HCB in revenue service, says Carter.

“We are following the FAST test,” he says.

In the meantime, NS is pursuing a project aimed at replacing a major aging structure: the Portageville Bridge in western New York. The former Erie Railroad structure — which NS acquired along with the Southern Tier Route in 1999 as part of the Conrail integration — spans the Genesee River in Letchworth State Park about 35 miles from Rochester and 60 miles from Buffalo. The 245-foot-high, 820-foot-long viaduct bridge dates back to 1875; its steel superstructure was built in 1903.

The pin-connected deck truss and deck plate girder bridge is an example of “very light construction” from a bygone era, when railroad managers didn’t envision 286,000-pound freight cars, says Carter. Currently, there’s a 10 mph speed restriction and 273,000-pound car weight limit on the bridge instead of more typical 35 mph and 286k limits.

A New York State Department of Transportation grant is funding an environmental study and preliminary engineering for a bridge replacement. Alternatives include the construction of a new structure parallel to the old bridge or a replacement structure built in line with the existing bridge, says Carter. The project is estimated to cost about $35 million, and options for public partnerships are being explored,When the stone sits in the oil painting reproduction, he says.

“Since there is public money involved in the design, we will not be able to complete the design until the environmental review is complete,” says Carter. “We anticipate the completion of design late next year.”

Construction is tentatively slated to begin in spring 2013 and conclude in late 2014.

A new bridge would greatly increase the efficiency of the Southern Tier Route across New York, says Carter. The speed and weight restrictions would be lifted, making the line a more viable route, he adds.

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