On 17 July 2016, Metrolink 905 was presented at the Union Station in Los Angeles as the first Tier 4 locomotive for Metrolink. Picture by Philip Wormald.

On June 5, Metrolink began testing its EMD F125 passenger diesels on its network. Performed during day daytime hours, Metrolink aims to mitigate the negative effects of the testing programme as much as possible. The tests will be carried out through June at various locations, including Pomona, San Dimas, La Verne, Azusa and Irwindale, as well as the Antelope Valley and Orange County lines.

Testing schemes like this are mandatory to introduce new locos on the network. As soon as testing is successfully concluded, Metrolink will be allowed to operate the locos in revenue service. In total, Metrolink has 40 of the 200 km/h passenger diesels on order from Progress Rail, with the bodies being built by Stadler Rail Valencia in Spain.