Transportation's Role in Reducing U.S. Greenhouse Gas Emissions ...

� 3.5 Railroad Technologies
Currently, there are approximately
23,000 locomotives operating in the
United States (U.S. DOT, 2009;
Weatherford, 2008), including line-haul
locomotives that move freight over long
distances, and yard or switcher engines
that operate at or near a rail yard. Yard
engines are involved in disassembling
and combining freight cars into trains
and are equipped with engines between
1,000 and 2,300 horsepower, consuming
approximately 50,000 gallons of diesel
fuel per year (CARB, 2008b). Yard
locomotives with horsepower ratings
less than 1,000 are referred to as
“industrial locomotives” or “critters”
and are expressly exempt from EPA
locomotive emissions standards (EPA,
1997). Line-haul locomotives tend to be
larger than yard locomotives and over
time, are increasing in size to be able to
carry more freight efficiently
(Weatherford, 2008; Shurgart, 2007).
Today’s line-haul locomotives have an
average horsepower rating of 3,600
(Weatherford, 2008), with the largest
Transportations Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
Railroad Technologies
Per Vehicle GHG Reduction:
• Common rail injection systems: 5–15%
• Genset engines: 35–50%
• Hybrid yard engines: 35–57%
• Hybrid line-haul operations: 10–15%
• Light weight railcars, aerodynamics, wheel to rail
lubrication: 4–10% individually
• Improving load configuration for intermodal
trains: up to 27%
Confidence in Estimates: Moderate
• Benefits of some technologies not welldocumented
Key Cobenefits and Impacts: Positive
• Some technologies can significantly reduce
pollutant emissions in populated areas
Feasibility: Moderate
• Mostly limited by railroad operator interest in/
acceptance of new technologies
Key Policy Options:
• Financial incentives for purchase of retrofits
engines having a horsepower ratings greater than 6,000 (Stodolsky, 2002). A line-haul
locomotive consumes between 250,000 and 500,000 gallons of diesel fuel per year (CARB,
2008b). Most rail fuel consumption and emissions—over 90 percent for Class I railroads
that carry most of the freight in the United States—are associated with the operation of
line-haul locomotives (Table 3.5A). The Class I railroads consume approximately 4 billion
gallons of diesel fuel per year to move 1.8 trillion ton-miles of cargo. 64
64 Class I railroads, which currently include the seven largest railroads in the U.S., account for
67 percent of the industry’s mileage and 93 percent of its freight revenue. They concentrate
largely (but not exclusively) on long-haul, high-density intercity traffic lanes. Class II and III are
smaller, regional and local railroads. In addition, switching and terminal (S&T) railroads
primarily provide switching and/or terminal services (AAR, 2009).
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