Metra SD70MACH
Look at this newly arrived remanufactured locomotive for Chicago’s Metropolitan Rail (Metra) system: the Electro-Motive (EMD) SD70MACH from Progress Rail! It is and will be Metra’s first diesel locomotive of several characteristics explained below:
- The first six-axle model since the EMD F40C
- The first hood unit geared for passenger duty
- The first with alternating current traction motors
- The first mainline unit to have Tier 3 exhaust emissions certifications
The F40C was the first and, for a while, the only EMD six-motor locomotive originally built with the electrical head-end power system. However, the SD70MAC is no stranger to HEP because the Alaska Railroad requested that feature on some of its MAC units for both freight and passenger trains as Amtrak does not access the 49th state. Interestingly, EMD concluded production of the SD70MAC in 2007, two years after the Tier 2 emissions standards were enforced by the U.S. Environmental Protection Agency. These regulations did not apply to Alaska, which was the reason behind the late production of the locomotives. Some of Metra’s diesels such as the F40PH use the main engine for head-end power while others, like the F40C and F59PH, contain an independent HEP engine as a more efficient method. Passenger locomotives equipped with AC traction typically utilize an inverter system to supply electricity for both the traction motors and head-end power, so both the Alaska and Metra SD70MAC’s would probably fit into that category.
The last new locomotives purchased by Metra are the MPXpress MP36PH-3S, built by MotivePower, Inc. (MPI) in 2003. Since then, the agency has focused on rebuilding its older units and purchasing pre-owned units as a more cost-effective approach to modernize its fleet. At least four MP36 units had their static HEP inverters swapped out for more reliable Caterpillar HEP diesel engines; these are redesignated as MP36PH-3C. Between 2014 and 2018, Metra purchased three F59PH locomotives from Montreal AMT and 21 streamlined F59PHI units from Amtrak. Both classes are the agency’s first models powered by the EMD 710G diesel engines.
When it comes to exhaust emissions, all of Metra’s F40 classes as well as the F59’s are rated Tier 0, although many of the older units have been rebuilt with microprocessor controls and upgraded to Tier 0+ certifications. The overhauled MP36 units were also upgraded from Tier 1 to Tier 1+. Unfortunately, there have been many complaints about the air pollutants emitted primarily by the F40’s and even the younger F59’s. Metra was anxious to find a much cleaner locomotive while avoiding the cost of buying a brand new one. While the SD70MACH is classified as a Tier 3 model, the very first Tier 3 locomotives delivered to Metra are two EMD GP23ECO’s, which are propelled by eight-cylinder 710ECO engines albeit intended for switching operations. Except for the MPI-built MP36, all of Metra’s locomotive classes (including pre-owned units) were originally constructed by Electro-Motive, and the agency has once again turned to EMD for its cleanest locomotives available at the lowest possible price and, of course, with the latest technology ensuring high reliability.
UPDATE: Here's an extra article that has just been written after my blog post about the Metra SD70MACH. You’ll learn additional details such as the origins of the first MACH unit and its 14 siblings, the history of Metra’s six-axle motive power, and the AC-motored diesel’s inverter system for both traction and head-end power. I find this article very useful.
Photo courtesy of Metra
