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In early September, CARB staff held a workshop addressing the draft statewide emissions inventory of locomotives for the 2020 calendar year, including a forecast to calendar year 2050. The baseline data for the number of locomotives (population) and activity (in megawatt-hours) was provided by the Union Pacific Railroad and BNSF Railway as part of the Memorandum of Understanding (MOU) that the Class 1 railroads signed with the CARB and South Coast Air Quality Management District.

Much effort was expended by CARB staff to adjust the baseline locomotive population and activity assumptions by analyzing the following factors:

  • Rate of increasing and decreasing tier groups based on remanufacturing patters
  • Rate of locomotive retirements after total service life
  • Growth in activity due to increases in freight movement
  • Pattern of “backfilling” of retired locomotives with those in storage

Even though the impact Covid-19 has had on reducing car loadings was acknowledged, as well as the large number of parked locomotives, CARB's inventory forecast assumes a 2.19% annual increase in activity, on a statewide basis, through calendar year 2050. CARB's presentation also highlighted the very low penetration of Tier 4 locomotives, which were first required for newly built locomotives beginning with the 2015 calendar year. CARB further acknowledged that “future replacements will primarily be Tier 1+ and Tier 2+ with only moderate Tier 3 and Tier 4 purchases,” which casts some doubt on the benefits that a Tier 5 locomotive standard would bring.

In addition to line haul locomotives, CARB's inventory also includes switch locomotives, short line (Class 3) railroads, and passenger locomotives. Altogether, CARB's inventory forecasts 82 tons per day of nitrogen oxides (NOx) emissions in 2020, declining to 52 tons per day by 2050 on a statewide basis. Even though this emissions category is relatively small (compared to approximately 532 tons per day of NOx for on-highway sources in 2020), CARB continues to include locomotives in their 2020 Mobile Source Strategy, based on the belief that health risk from diesel exhaust is elevated near railyards. To address this, CARB will complete a study of the cancer risk and mortality/illness rates due to locomotives, which will be presented as the basis for a Locomotive Regulation webinar scheduled for fall 2020.

Trinity Consultants has assisted clients operating locomotives with ongoing CARB engagement and has been closely following the development of these new regulatory concepts. For more information or compliance assistance, please contact Allan Daly or Jim Lyons of Trinity's Mobile Source and Fuels business line.