The California Air Resources Board (CARB) issued a Tier 4 Verification Certificate for Metrolink’s new, clean diesel locomotives after Emissions Verification testing was successfully completed. The testing and certification confirm that Metrolink’s locomotives continue to operate at the US Environmental Protection Agency’s (EPA) highest standards for diesel locomotives — Tier 4 — even after the units have been in service for an extended period. At the time of testing, the locomotive analyzed had logged more than 100,000 miles of service.

“Tier 4” is the most stringent designation from the EPA for engines to dramatically reduce emissions. Every year, Metrolink reduces greenhouse gas emissions by an estimated 130,000 metric tons.

Metrolink has worked with its Member Agencies, the California State Transportation Agency (CalSTA), and regulatory partners including the South Coast Air Quality Management District (SCAQMD) for funding support of the 40 new Tier 4 locomotives. The certificate is a requirement to receive previously awarded grant funding from SCAQMD.

The total project cost of $280 million was largely funded from the SCAQMD through the Carl Moyer Memorial Air Quality Standards Attainment Program, which granted funding of $110 million. Additional funds were provided by state ($132 million), federal ($21 million), and local ($17 million) sources.

Metrolink currently has 37 of the planned 40 Tier 4 locomotives operating in its fleet, with the final three scheduled to be placed in service this fall.

Tier 4 locomotives reduce emissions between 65% and 85% compared to Tier 2 and Tier 0 locomotives, respectively, which previously were in Metrolink’s original fleet. The last of Metrolink’s 38 Tier 0 locomotives was removed from service earlier this year.

As part of the CARB Tier 4 Verification Certificate testing, sensors capable of detecting precise levels of nitrogen oxide (NOx), the primary factor to smog, and particulate matter, which leads to soot, were mounted over the locomotive’s exhaust stack to record emissions.