The contract includes a base order of 10 locomotives, plus an option to purchase up to 10 additional locomotives. Metrolink has allocated $129.4 million for the purchase of the locomotives.
LaGrange, Ill.-based EMD is a subsidiary of Progress Rail Services Corp., itself part of Peoria, Ill.-based Caterpillar, Inc.
"This is a significant milestone in Metrolink's efforts to operate the most efficient and environmentally friendly commuter rail system in the nation," said Board Chair Richard Katz. "It demonstrates our commitment to our neighbors and to doing our part to clean up the air in Southern California."
The first three demonstration locomotives are scheduled to be complete in the fall of 2015, Metrolink said.
Besides reducing emissions, the EMD locomotives will sport more horsepower than Metrolink's current locomotive fleet, allowing longer trainsets.
In a related move, Metrolink will test alternative fuel sources in future operations. Metrolink will make the first locomotives replaced by the new Tier 4s available to the South Coast Air Quality Management District for the purposes of experimentation with various alternative fuel technologies expected to be commercially available in the next decade.