Railway Track & Structures - April 2008 - (Page 45)

clear distance to live wires. In 2000, electrification was added to the bridge. The high-voltage, negative feed lines of the system were mounted on the outboard faces of the through trusses, just below the level of the upper chord. This combined with the catenary system mounted immediately above each of the two tracks, prevented inspection access to the entire top half of the trusses while the electrification system was live, and the hands-on inspection work could only be performed while at least one track was out of service, and the electrification system for that track de-energized and grounded. Night work would be a possibility for work requiring taking a track out of service with the electrification system de-energized. However, inspecting a structure at night, even with expensive floodlights, is not usually effective. The field team was able to arrange with Amtrak to piggyback the inspection with planned 55-hour weekend singletrack outages being made for other construction activity. This weekend work permitted hands-on inspection of the upper portions of the truss work during daylight hours. In order to inspect the underside of the bridge and to provide as little interference with rail operations as possible, the inspection work was performed using a man-lift on a barge. The barge was propelled by a push-tug. A safety and inspection powerboat was also provided. Work in the navigable channel of the Connecticut River was coordinated with river traffic. During the summer months, the Connecticut River has constant recreational boating traffic. The bridge includes a 100-year-old rolling lift bascule draw span. Inspection of the electrical and mechanical facilities of these bridges requires trained individuals who are knowledgeable in and experienced with: movable bridge technology and practices, railroad operations environment, interaction of structural-mechanical-electrical systems of the movable bridge, signaling interface with the electrical operating system, and electrification interface with the bridge draw span operations. Acknowledgements We express our thanks to the following individuals and organizations for efforts related to the subjects of this paper: David Gerber, P.E., Associate Engineer, Hardesty & Hanover, for rating analysis of Tunkhannock and Martin’s Creek Viaducts. David Killingbeck, P.E., Manager Structures Inspection at Amtrak (Project Manager for Little Hell Gate Bridge inspection project). Kenneth Kulick, P.E., Director Structures Design at Amtrak (Project Manager for Connecticut River Bridge inspection project). James Richter, P.E., Deputy Chief Engineer Structures at Amtrak (review of draft paper). John Unsworth, P.E., Manager Structures Planning & Design at Canadian Pacific Railway (Tunkhannock and Martin’s Creek Viaducts, Project Manager for inspection project). John Wood, P. E., Senior Structural Engineer, Structures Planning and Design, CP Railway for review of load ratings of the viaducts. References 1. Ammann, Othmar, ASCE Transactions Vol. LXXII, Paper No. 1417 presented Nov. 21, 1917. www.rtands.com Railway Track & Structures April 2008 45 http://www.transalert.com http://www.rtands.com

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Railway Track & Structures - April 2008 Contents On Track Industry Today Supplier News AREMA News NRC News TTCI R&D Railroads Seeking More Advanced Systems to Handle Materials SKOL Bounces Back From Summer Flood Landmark Railroad Bridges Need Inspection, Too Products and Literature People Calendar Sales Representatives Advertisers Index Website Directory Professional Directory Classified Advertising Chicago Perspective

Railway Track & Structures - April 2008

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