Tier 4 Rules

July 20, 2016, 8am PDT
Forty so-called Tier 4 locomotives, a U.S. Environmental Protection Agency designation requiring a dramatic reduction in particulate and nitrogen oxide emissions, will be joining Metrolink's fleet covering 512 track miles in six counties.
Los Angeles Times
April 16, 2014, 7am PDT
According to a new EIA report, the cost advantages of liquefied natural gas make it an attractive alternative to diesel fuel for major U.S. freight railroad companies. Hybrid diesel-electric locomotives on order for 5 states will power HSR routes.
Progressive Railroading
March 24, 2014, 6am PDT
Thanks to the 2010 federal requirement of ultra-low sulfur diesel fuel and new Tier 4 emissions standards by the EPA, particulate emissions from non-road diesel engines, including agricultural and construction equipment, have been reduced by 99%.
Environmental Health News