Caption: General Electric has begun shipping the first of its Tier 4 “Credit User” locomotives to customers this month. Both Canadian National and BNSF Railway are the first to receive new locomotives from GE’s Erie and Ft. Worth, Texas, plants, respectively. A Credit User locomotive is essentially a Tier 3 emissions-equipped locomotive built after the Jan. 1, 2015, implementation date for Tier 4 emissions. GE ES44A6 2037 is at MacMillan Yard shops undergoing set up and static load testing on March 15/2015.