The GE AC44C6M is a 4,400-horsepower (3,300 kW) diesel locomotive that was built by GE Transportation Systems, and rebuilt by GE, American Motive Power, Inc., and Norfolk Southern's Juniata and Roanoke Shops, starting in September 2015. The AC44C6M retains the 16-cylinder 7FDL-16 prime mover used in the core locomotive prior to rebuilding, but features GE's alternating current 5GEB13B7 traction motors. Externally, the rebuilds have received new wide-nosed cabs and a new front hood section of the same design as on the ES44AC, while retaining the underframe and engine and radiator compartments of the original Dash 9 units. Internally, the AC44C6M features a new under-floor air conditioner, cab signals, LSL, DPU systems, PTC, and ECP braking ability, a significant technological improvement from the GE Dash 9-40C units. [3]
Norfolk Southern Railway (NS) is a significant operator of this model. All 124 of their remaining Dash 9-40C units, numbered 8764–8888 (excluding 8798, which was wrecked in 2018) were rebuilt from 2015 to 2018 and numbered 4000-4124.[1] The railway plans to also upgrade all of its Dash 9–40CW units to the same standard.
Union Pacific Railroad (UP) also operates a significant number of similar locomotives, and plans to send 1,000 units to GE for overhauls.[4]
Originally Built as C40-9s and C40-9Ws. 4001 wrecked, repaired and new horn placed. 4063 wrecked in 2018 and retired. 4000-4005 & 8520 were painted into special paint liveries, 8520 classed as AC44C6CF. 8520 was retired and sold.
Originally Built as GE AC4400CWs. Units 7000-7199 are rebuilt from 1-173 series and 7200-7299 are rebuilt from 200-onwards. These units are classed as CM44ACs (AC4400CWMs).
