The EMD SD90 Mac (also known as the EMD SD90MAC-H or SD90/43MAC) is a type of diesel-electric locomotive produced by Electro-Motive Diesel (EMD), a subsidiary of the Progress Rail Services Corporation. It is part of the EMD 90-series locomotives and was first introduced in 1995.
The SD90 Mac is designed for heavy-duty freight service and has a maximum horsepower of 4,300. It uses a 16-cylinder, 4-stroke diesel engine and AC traction motors to drive the wheels. The locomotive is equipped with advanced electronic controls, including a microprocessor-based control system that allows for better fuel efficiency and reduced emissions.
The SD90 Mac has been used by several North American railroads, including Union Pacific, Canadian National, and Canadian Pacific. It is also used by some railroads in other countries, such as Australia and Saudi Arabia. However, the production of the SD90 Mac was discontinued in 2015, as EMD shifted its focus to producing locomotives with newer technologies, such as the EMD Tier 4 locomotives.