The company began doubling its heavily used southern Arizona line from Los Angeles to El Paso in the middle of the past decade to allow it to transport more containers from California ports to the interior United States. Because the recession cut freight movement and Union Pacific's revenue, the company slowed the remaining work in 2009 and then stopped it this year, said Zoe Richmond, a spokeswoman.
The project was about 60 percent done and was supposed to be finished in 2012. Richmond added that it is unknown when the project will resume.
"The work slowed down because there isn't the business need," she said.
Business has picked up, though, an indication that the economy is improving as well. Union Pacific said that through mid-March, the number of containers, cars and truck tractors carried on trains this year had increased 12 percent compared with the same period a year earlier.
In January, the company began replacing miles of rail lines, particularly in rail yards in Phoenix and Tucson and on a main line between Casa Grande and Yuma. The $42 million being invested includes $18 million to buy concrete ties that are made of cement produced near Tucson.
Union Pacific has been
steadily replacing wooden ties with concrete ones on its more heavily used
lines across the country because they don't weather as fast and aren't
susceptible to termites. Even though wooden ties are soaked in creosote, an
oily preservative, they don't hold up well in the Arizona desert, Richmond
Union Pacific began using concrete ties when the second track was added to the Sunset line between Los Angeles and El Paso in 2005, and the railroad added more this year on a line between Maricopa and Gila Bend.
Concrete ties are just one of the innovations that have come to the rail industry. Rails can now be installed mechanically en masse, and computers have taken the place of cabooses.
Most of Union Pacific's concrete ties are being installed with its "track-renewal train," a mile-long machine called the TRT 909 that can install up to 5,000 ties in a 12-hour day. It includes 30 rail cars each carrying 210 concrete ties and three cranes used to move the concrete ties forward.
At the front of the machine, old wooden ties and rails are picked up, and at the back, the new ties are automatically dropped into place and new rails threaded onto the ties. It also can be used for wooden or composite ties.
When the work in Arizona is done, crews will have installed an estimated 156,000 wooden and 58,000 concrete ties and 24 miles of welded rails.
The work is expected to be done by the end of May.