Throwback Thursday

By Keith MacCauley

 ARR 4001  

 Alaska Railroad SD70MAC ARR 4001 was built by GMDD London in December of 1999. Something of a pioneering unit, No. 4001 was the first AC unit purchased by the remote state-based railroad and uniquely equipped with HEP to facilitate passenger train assignments. The Alaska RR would acquire a total of twenty-eight SD70MAC’s; ARR 4001 – 4016 (built 1999/2000), ARR 4317 – 4324 (built 2004) and ARR 4325 - 4328 (built 2007).

The six axle SD70MAC was EMD’s first mass production AC locomotive. Following a quartet of SD60MAC testbeds, EMD/GMDD would go on to produce more than a thousand SD70MAC’s between 1993 and 2004. So pleased with their fleet, the Alaska RR would convince GMDD to supply four additional SD70MAC’s in 2007 after the builder had moved on to alternate catalogued SD70 model variants. Burlington Northern, followed by Burlington Northern Santa Fe would receive the Lion’s share of SD70 MAC production with almost eight hundred rostered. Of note, the SD70MAC would represent the last time the builder would advance locomotive development ahead of longtime rival GE. Erie’s landmark ‘AC’ series, introduced shortly thereafter, would go on to dominate the industry, with follow up variants still in command today.