In an effort to accelerate the movement to zero- or near-zero emission locomotives, the California Air Resources Board (ARB) has petitioned the US EPA take action to adopt more stringent emission standards for locomotives. These new standards are to include standards for newly manufactured locomotives (which ARB refers to as “Tier 5”), and a new standard for Tier 4 locomotives upon remanufacture.
ARB is also requesting new remanufacturing standards equal to or more stringent than current Tier 4 emission levels for Tier 2 and 3 locomotive engines. ARB Chair Mary Nichols said the moves are needed to clean up the air in “high-risk” communities in and around the nation’s railyards.
The proposed emission standards would cut toxic and smog-causing emissions by 85% for diesel particulate matter (PM) and 66% for oxides of nitrogen (NOx) below current Tier 4 levels. Newly manufactured locomotives would have some zero-emission mile capability.
|Top: Existing federal standards. Bottom: ARB’s proposed Tier 5 standard. Source: ARB. Click to enlarge.|
ARB said that the proposed standards recognize advancements in technology that support zero-emission rail operation in impacted communities while also providing nationwide fuel savings for the railroads.
EPA first established emission standards for hydrocarbons (HC), NOx, and PM for locomotives and locomotive engines in 1998, with revisions over time.
In 1998, EPA adopted Tier 0, Tier 1, and Tier 2 emission standards for original manufacture and for subsequent remanufactures of locomotives; these were applicable to locomotives with engine model years from 1973-2011.
In 2008, US EPA amended the 1998 locomotive regulation, establishing a Tier 3 and a Tier 4 emission standard, as well as stricter remanufacturing standards for remanufactured Tier 0-2 engines.
he new Tier 3 PM emission standards went into effect for engine model years 2012-2014 for line haul locomotives and represented a minor step change. The Tier 4 line haul locomotive standard, effective in 2015, requires a reduction of NOx and PM emissions of 90% for NOx and 95% for PM, relative to pre-Tier 0.
The key technologies used to achieve these reductions in NOx and PM emissions are exhaust gas recirculation and improvements to the cooling system. Tier 4 locomotives are commercially available and are now being phased in.
In the formal petition submitted for US EPA Rulemaking to reduce locomotive emissions, Nichols made it clear that recent studies have found that there are significant diesel exposure disparities by race and income among residents living in close proximity to most of the major railyards in California.
Nichols acknowledges that many steps have already been taken to clean up emissions from the nation’s complex freight delivery network. National locomotive emissions and diesel fuel standards, CARB agreements with railroads, California emission standards for drayage trucks and cargo equipment, and private and public investments in cleaner equipment are reducing overall emissions and health risk near our major railyards.
However, CARB believes that more can be accomplished, and that to deliver on the collective responsibility to improve conditions on the ground for overburdened communities, new action by US EPA to require a transition to zero and near-zero emission locomotives is necessary.