Union Pacific will hold the distinction of being the first Class I railroad to order freight locomotives with Selective Catalytic Reduction (SCR) catalysts as part of its Tier 4 emissions equipment. SCR, which uses urea, has generally been found on passenger locomotives and other non-Class I railroads. To date, the Class I railroads have insisted that Tier 4 freight locomotives are designed without it, citing the additional cost of the material, ground storage, and pumping facilities to accommodate it.
The 10 locomotives are scheduled to be numbered in the UPY Nos. 1000-1009 series when delivered.
This will be Progress Rail’s first order for the EMD24B. The company constructed PR24B demonstrator No. 24 in late 2016 and has been testing in California on the Pacific Harbor Line in the Los Angeles basin.

