Railway Track & Structures - October 2008 - (Page 13)

Technical article railroad-highway crossing has been developed that allows the advantages of grade separation without the expense of embankments, major construction and property acquisition normally encountered with such projects and eliminates changes in elevation and corresponding gradients normally encountered. This system essentially provides a grade separation of only a few inches, with the highway passing over the railroad track. When a train approaches the highway crossing, the part of the crossing obstructing the railroad track retracts and forms a barrier gate preventing highway vehicles from fouling the tracks. This idea originally came about as a means to provide safe high-speed rail transportation in North America, where great distances separate major population centers and existing railroad tracks connecting these population centers are crossed at grade by many highways and secondary roads. While 50 or more years ago, relatively high-speed trains in the 70 to 90 miles per hour range were able to navigate these tracks with relatively few accidents, present-day highway travelers are less aware of the presence of railroad trains and are more likely to attempt to drive around or through lowered crossing gates. By tilting the crossing itself up in front of the highway vehicle, an impenetrable barrier gate is formed. This device can be completely automated and can be combined into or with existing signal and train A Railroad Highway Crossing by Terry L. Koglin, High Speed Associates (608) 756-2067 • koglintl@yahoo.com control systems. Advantages Incidental to its basic purpose of allowing high-speed rail traffic on existing railroad right-of-way, it was found that the Railroad Highway Crossing provides many other advantages to the railroad. These advantages include: Flangeways in the crossing that can foul with ice, snow, debris or dirt are eliminated. The Railroad Highway Crossing provides a solid barrier to prevent automobiles from fouling rail traffic. The barrier can be constructed to be as rigid as necessary so that any expected vehicle, traveling at any expected speed, will be stopped without fouling the railroad tracks. The railroad track is completely accessible through the gate/crossing for maintenance, rail or crosstie replacement or any other work on the track. The gate/crossing hinge points can be placed so that the full required horizontal railroad clearance width can be provided with the gate/crossing raised. The highway can have smooth alignment, in spite of the track being on a curve with superelevation or on a grade of any steepness. The railroad tracks in 2008 Upcoming Committee Meetings October 5-6 October 7-8 October 16 October 16-17 October 28-29 October 28-29 November 6 November 12 November 19-21 December TBA Committee 34 - Scales Committee 15 - Steel Structures Committee 33 - Electric Energy Utilization Committee 8 - Concrete Structures & Foundations Committee 2 - Track Measuring Devices Committee 30 - Ties Committee 28 - Clearances Committee Chairs' Meeting Committee 36 - Highway-Rail Grade Crossing Warning Systems Committee 33 - Electrical Energy Utilization Kansas City, MO Chicago, IL Newark, NJ Des Moines, IA Minneapolis, MN Savannah, GA Phoenix, AZ Orlando, FL Omaha, NE Philadelphia, PA such cases will lay under the lowered Railroad Highway Crossing with varying vertical clearances between top of rail and bottom of gate/crossing superstructure. For instance, if a highway 100 feet wide having no grade crosses the railroad at a 90-degree angle and the railroad is on a one-percent grade, the difference in elevation between the top of rail and highway running surface of the gate/crossing will be one foot more on one side of the highway than the other. But there will be no noticeable effect on the highway itself, nor, of course, will there be any disturbance of the railroad tracks. A highway on a grade, crossing a railroad track, can have a continuous slope through the crossing, avoiding misalignment of track due to impact from highway vehicles. In this case, a highway, say on a six-percent grade, crossing a single track railroad with no curvature or gradient at the crossing, will have vertical clearance between the bottom of the Railroad Highway Crossing and the top of one rail about 3.5 inches more than at the other rail, assuming constant depth of Railroad Highway Crossing. The highway, if on a curve, can be superelevated through the Railroad Highway Crossing. Any combination of railroad and highway alignment, gradient and curvature can be accommodated by the Railroad Highway Crossing without the alignment of the highway affecting the railroad, and without the alignment of the railroad causing a deviation in the highway. The system can accommodate any angle of crossing, but is especially valuable in the cases where the highway crosses the railroad at an extremely acute angle. Normally, these crossings are especially vulnerable to automobile-train collisions, and are dangerous Railway Track & Structures October 2008 13 www.rtands.com http://www.rtands.com

Table of Contents Feed for the Digital Edition of Railway Track & Structures - October 2008

Railway Track & Structures - October 2008 Contents On Track Industry Today Supplier News AREMA News NRC News TTCI R&D Railroads Building Solid Foundation for More Capacity with Crossties Safety in High Density Areas M/W Challenges: CN Places New Bridge in Only Six Hours Products and Literature People Calendar Website Directory Advertisers Index Sales Representatives Professional Directory Classified Advertising Chicago Perspective

Railway Track & Structures - October 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.