Environmental Engineering Reference
In-Depth Information
Chemicals and allied products
Farm products
Nonmetallic minerals
Miscellaneous mixed shipments
Coal
Food and kindred products
Metallic ores
Metals and products
Waste and Scrap
Other commodities
Figure 2.3
Classes of products carried by freight railroads in the United States. (Association of Ameri-
can Railroads, 2008)
as haulers of freight. A train can haul a ton of freight 423 miles on 1
gallon of diesel fuel, about a three-to-one fuel effi ciency advantage over
eighteen-wheelers, and the railroad industry is increasingly touting itself
as an ecofriendly alternative to the trucks that have dominated freight
transport for decades. To handle their new green status, the railroads
spent nearly $10 billion in 2008 to add track, build switchyards and
terminals, and open tunnels. According to the DOT, freight rail tonnage
will rise nearly 90 percent by 2035.
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Employment in the industry has
increased accordingly. In 2002, the major railroads laid off 4,700
workers; in 2006 they hired more than 5,000.
The rail network is privately owned, was largely built almost one
hundred years ago, and includes over 76,000 railroad bridges, mostly
built before 1920. Each freight car is carrying more weight today over
old bridges. The condition of the bridges is considered proprietary and
is known only to the executives of the railroad companies. About 41
percent of the bridges are made of wood, 36 percent of steel, and 23
percent of masonry.
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Bridges and tunnels are likely to cost more to
repair—and as much as $100 million to replace—than other components
of railroad infrastructure networks, such as tracks and signals. As a
result, railroads are more likely to invest in other components sooner
and to consider extensive bridge or tunnel repair or replacement as one
of their last investment options.
