HIGHLIGHTS FROM THE SEPTEMBER 2008 ISSUE
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Multi-tasking muscle machines
Track time is a precious commodity. Railroads need high performance m/w machines to get precision work done quickly, with minimum disruption to train operations.
If the section crew with a handcar can be compared to a Ford Model T, today’s high-speed, high-production maintenance-of-way machines are like all-wheel-drive, high-horsepower SUVs. In the hands of skilled employees, these marvels of computer-guided machinery can do many things at once, with an astonishing level of precision. This ability is especially critical on railroads that are pressed for track time and capacity, moving high-tonnage traffic on main lines that must be able to withstand more million gross ton-miles than any railroader of bygone days could have imagined possible.
Two companies, Harsco Track Technologies and Plasser American, are specialists in these multi-tasking muscle machines, domestically and internationally. Here’s a look at some of the latest developments in power, precision, and performance.
Put a Tiger in your tamper
The Mark IV Tiger Tamper, with a peak production rate of 36 ties per minute, single insertion on wood tie track, is a recent development of Harsco Track Technologies. The machine is an advancement in technology from the standard Mark IV that has been manufactured by Harsco Track Technologies since 1992, according to HTT’s Robert Newman.
The heart of the control system for the Tiger Tamper is the Jupiter Control System Tie Finder, which “is effective on wood tie track with tie plates, and on concrete ties,” says Newman. “It uses the magnetic signature of the tie plate on wood ties, and the magnetic signature of the smaller clip and clip holder on concrete tie track. An important design feature for the Tie Finder is that it can transition from concrete to wood ties and from wood to concrete ties without operator input.”
The MK IV Tiger Tamper is based on the “tried and proven Mark IV,” Newman says. The front of the machine is a virtually standard Mark IV. The rear section is a trailing unit carrying a second set of standard Tamper Vibrators. The trailing unit has one axle in the rear, and the front of the trailing unit is supported by the rear axle of the Mark IV.
Here’s how the Mark IV Tiger Tamper works: The Tie Finder first records the location of each tie and stores it in its computer control system’s memory. Then, the set of lead workheads automatically locates and tamps the first tie, with no operator control required. Next, the set of lead workheads skips the next tie in sequence and tamps the second tie in the sequence. As the tamper advances, the rear set of workheads tamps the tie skipped by the lead set of workheads.
And now, for something completely different: HTT’s Stoneblower provides a method of surfacing track that is an alternative to tampers. Prior to the 1950s and the development of tamping machines and mechanized track gangs, surfacing was done manually, by trowelling or by measured shovel packing. Trowelling was the North American method, and it was similar to measured shovel packing, which was practiced in the United Kingdom and other countries around the world.
HTT now offers the Stoneblower as a contract service in North America. The company lists several advantages, including: surface geometry durability at least two times better than a tamper; average durability about three times better than a tamper and, in poor ballast conditions, even higher; no ballast damage from a tamper; reduced track occupancy time; considerable savings on ballast and ballast distribution; and treatment of low spots only, so track is not raised under bridges and other areas where existing overhead clearances must be maintained.
In 2004, HTT and Union Pacific decided jointly “to take a quantum leap in technology rather than to continue evolution of existing technology for track renewal,” Newman says. “The collaboration spawned the TRT-909, which offers significant advancements over the previous generation of track renewal machines and is “the quantum leap in technology that we envisioned.”
The TRT-909, which entered service in 2005, takes full advantage of ties preloaded with clips and insulators by heating the rail to the neutral temperature within the machine’s length and then fastening the clips. Rail heating is accomplished through electrical induction in both rails, a safer and faster method than propane heaters. Higher-speed gantries are made possible with an improved suspension system with bogies. The entire TRT-909 is controlled by HTT’s Jupiter Control system, providing high reliability and self-diagnostic capability. For clipping, the machine features the new “nipper clipper” workstation.
Able to fill tall orders in a single pass
Plasser American Corp. offers an assortment of high performance equipment ranging from tamping machines to ballast regulating and distribution machines to ballast undercutting/cleaning machines. Examples are the 09-3X DYNAMIC TAMPING EXPRESS, BDS-100/200 Ballast Distribution System, and RM-2003 and RM-802 Ballast Undercutting/Cleaning Machines.
“The main advantages of the 09-3X DYNAMIC are that the machine is capable of tamping three ties at a time, which increases productivity over a single tie tamper considerably,” says Patrick Hofstadler, sales administrator. “As a DYNAMIC-type machine, it has an integrated Dynamic Track Stabilizer, which stabilizes the track immediately after the tamping process, thus eliminating any delay of stabilizing when two separate machines are used and the need for two operators.”
The BDS-100/200 is a high performance ballast regulating machine that plows and brooms ballast in a single pass. It is capable of picking up excess ballast, storing in its ballast hopper or in MFS-Type Ballast Conveyor/Hopper Cars that can be coupled between the two units, and distributing the ballast in areas where it is needed, such as switches, road crossings, and track shoulders. “The high working speed of the BDS-100/200 allows it to work together with high-speed, multiple-tie tampers with ease,” Hofstadler says.
The RM-2003 and RM-802 are high output ballast undercutting/cleaning machines. “Fitted with a dual-ballast screening system, their cleaning capacity outperforms single screen machines considerably.” Hofstadler says. The RM-802 is a 205-foot-long, 243-ton, 1,580-hp machine that performs several operations at once. The Ballast Pick-up Unit picks up pre-dumped new ballast and moves it onto conveyor belts. Then, a transition conveyor belt fills the first of several MFS-Type Ballast Conveyor/Hopper Cars. A cutting chain excavates the existing ballast and passes it via conveyors onto a screening unit, which is equipped with two shaker boxes that can be adjusted to compensate for curve superelevation. Reusable ballast is separated from waste material, and conveyors transport the waste material to the end of the machine for discharge. The cleaned ballast is mixed with the pre-dumped, picked-up, stored ballast and put back into the track directly behind the cutter chain. The RM-802 does all this at rates of up to 2,000 feet per hour.
The RM-2003 is equipped with a track lifting and slewing device that allows the track to be lifted to reduce the cutting depth, and to be shifted laterally to clear track side obstacles. Cleaned ballast is evenly distributed by an oscillating return conveyor and distribution plow, creating a uniformly compact layer of ballast under the ties behind the cutter bar. Directly ahead of the rear truck assembly is a Dynamic Track Stabilizing unit that provides stabilization ahead of the surfacing gang, reducing the possibility of track buckling after ballast cleaning. A slewable waste discharge conveyor allows waste material to be discharged to either side of the right-of-way, or into Plasser MFS-Type cars or open-top cars.
Photo by Harsco Track Technologies
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Copyright © 2007. Simmons-Boardman Publishing Corp.