The SD70MAC was the first production AC traction locomotive in the US
Burlington Northern Santa Fe 9400, the SD70MAC diesel locomotive that pioneered AC traction for freight service in the United States when it was built in 1993, has been donated by BNSF to the Illinois Railway Museum for preservation. The locomotive is a forerunner of thousands of diesels built with AC traction motors, a technology that has been universally adopted in the years since 9400 debuted.
Following testing during the early 1990s of freight diesels fitted with AC traction motors, Burlington Northern placed the first production order for AC traction motor-equipped diesels with EMD in 1993. The order, for 350 locomotives numbered 9400-9749, was constructed between November 1993 and mid-1996. The 4,000-horsepower locomotives were groundbreaking not only for their AC traction motors but also for their radial trucks, computerized control systems, sound-deadened wide cabs, and “desktop” engineer’s control layout.
BN 9400 was given stainless-steel handrails and participated in a formal dedication ceremony in Fort Worth, Texas, in January 1994. Alongside the new SD70MAC was Chicago Burlington & Quincy E5 9911A “Silver Pilot,” on loan from IRM along with the “Nebraska Zephyr” trainset. Following its debut, 9400 entered daily service with BN and later BNSF, remaining in revenue service for nearly 25 years. In becoming part of the IRM historic collection, BNSF 9400 joins historic EMD products including the first GP-type and first SD-type locomotives ever built as well as CB&Q 9911A, the last E5.
The Museum plans to restore 9400 to operation and eventually repaint it to its original appearance, but donations are needed to cover the costs of storage, mechanical work, and restoration. Click here to support the preservation and restoration of BN 9400.
