Metra receives first rebuilt SD70MACH
Remanufactured freight diesel marks return of six-axle power, first with AC traction motors
METRA’S FIRST SD70MACH locomotive has been delivered, marking the return of sixaxle commuter diesels to Chicago after more than a decade, as well as the introduction of AC power.
The locomotive is the first in a 15-unit order rebuilt from former Kansas City Southern/Transportación Ferroviaria Mexicana SD70MACs sourced from Progress Rail’s locomotive fleet. While the balance of the order will arrive in Metra’s current paint scheme, No. 500 was painted to commemorate the upcoming 50th anniversary of the creation of the Regional Transportation Authority in 1974.
In announcing arrival of the first unit, Metra highlighted the greater durability of AC power, noting that it currently replaces about 160 DC traction motors annually, while it has never had to change an AC traction motor in 14 years of operating AC-powered cars on the Metra Electric line.
The locomotives will also be Metra’s first with the B1-1B truck arrangement, in which the two axles closest to the fuel tank are unpowered. This allows four of the locomotive’s six AC inverters to be assigned to the traction motors, with a fifth used for HEP, and the sixth as a spare for either traction or HEP in case of inverter failure. When the SD70MACH is operating normally, the fifth and sixth inverters will alternate HEP duties to keep usage uniform across the equipment.
Under current federal emission standards, SD70MACs such as these would fall under the Tier 0 emission requirement, the lowest emission standard. Metra chose to upgrade the SD70MACHs to Tier 3 emissions, requiring the addition of flared radiators on the long hood to accommodate the additional engine cooling needed.
While six-axle commuter power has traditionally been rare, Metra has the most sixaxle experience of any agency in North America. The newest locomotive will be its fourth six-axle model, with its third truck configuration. Previously, it operated former Chicago & North Western E8s and Burlington Northern E9s, with the A1A configuration, as well as C-C-trucked F40Cs purchased new by Metra’s predecessor, the Regional Transportation Authority, in 1974. They were essentially a SDP40F with headend power instead of steam generators.
Metra expects to receive approximately one new SD70MACH per month starting in November. It has options for up to 27 more.
Revenue service is still some time off, with crew and mechanical training just begun along with resolving any bugs that inevitably arise during the delivery of a new locomotive order. That testing is not just going on at Metra; there’s also an SD70MACH at the Transportation Technology Center in Colorado. — Chris Guss