Article by Chris Brimley, Project Manager
At the end of 2015, Norfolk Southern unveiled AC44C6M locomotives 4000 and 4001. These two locomotives would be the beginning of a rebuild program that continues today and now numbers over 1000 units. These would be rebuilt at multiple locations and would be the end of an era of DASH 9s that had been king on NS rails for 20 years.
During the 10 years that NS has been rebuilding locomotives into the AC44C6M platform, there have been many changes to the designs, and it is my hope to remove the fog of what makes these different externally.
For all AC44C6M’s, the changes to the DASH 9 design are largely above the sill and ahead of the engine compartment cabinets. This includes new cabs as well as dynamic brake, inverter, and inertial cabinets. There are other, more subtle changes as well that I will note below.
Also note that there are many changes to the different deliveries of DASH 9s, but for this Time to Model, I will only be focusing on the items modified or replaced during the AC44C6M rebuild process.
2015-2018: Dash 9-40C Rebuilds
NS began with the oldest DASH 9s on the roster for the rebuild program. These, unfortunately, were the standard cab “Top Hat” Dash 9-40C, which were unique to NS. Over 3 years, NS chipped away at the 125 units, and by December 2018, this batch was fully rebuilt. What we have come to refer to as the “Early Rebuilds” are the most unique of all C6Ms on the rails. These units would be numbered from 4000 to 4124.
One of the unique features of the Dash 9-40C that was different from later NS DASH 9s was the stepwell design. These units were delivered with stepwells with 4 treads and an early tapered profile on the truck side. All later Dash 9-44CWs had a 5 tread stepwell with a later angled profile. During the rebuild program, the front stepwells would be converted to the later 5 tread design, but would retain the original tapered 4 tread design at the rear.
Only the Dash 9-40C had a high-mounted sand filler; with one exception noted later, all Dash 9-44CWs had low-mounted sand fillers.
These, as well as the intermediate rebuilds, had an auxiliary cabinet with a stepped design against the engine compartment.
The bulk of these units was rebuilt by Norfolk Southern at their Juniata and Roanoke shops. These units are identified by having the Sine Wave logo on the sides of the cab. The units in the standard “Horsehead” scheme were rebuilt by GE at Erie or Fort Worth. 4000 and 4001 are the only units to have been rebuilt by GE at American Motive Power, Inc.
2018-2021: Dash 9-44CW Rebuilds
2018 saw the beginning of the rebuilding of the Dash 9-44CW. Above the walkways, these were mostly similar to the early rebuilds as they used the same cab and cabinet designs. Below the walkways, these units were delivered with 5 tread stepwells, so they retained their design and didn’t end up with the unusual 5/4 tread design.
The auxiliary cabinet designs were applied to units that were rebuilt through 2021. We have identified one unit rebuilt in November 2022 that received a straggler stepped cabinet. The road numbers associated with this design run from 4125 to 4500, as well as the one known oddball number 4522.
During the rebuilding process of these locomotives, GE Transportation was merged with Wabtec in February 2019. Wabtec would then consolidate its rebuild program to Fort Worth, and the last rebuild unit rolled out of Erie in October 2019. That following December, the last AC44C6M was rebuilt at Roanoke, and NS would then close it shortly after, and all work was now being performed at Juniata.
2022-2024: Dash 9-44CW Rebuilds
This generation of rebuilds saw the introduction of an auxiliary cabinet design that removed the step. This is similar to what Union Pacific, CSX, and Canadian Pacific have been using on their rebuilds. The cabinet had a flat top and the doors at the inertial compartment on the fireman's side changed to a wider design. The vent also went from being square to rectangular. On the engineer's side, the doors were widened and the grill was pushed back.
In 2023, Wabtec began again to rebuild AC44C6Ms at its Erie shops.
2024: ex-GECX/BNSF Dash 9-44CW Rebuilds
From July through December 2024, 25 former GECX/BNSF Dash 9-44CW locomotives were rebuilt for NS at Wabtec’s Erie facility (NS 4856-4880). These units were largely scrubbed of all features, making them look like BNSF units. The Gullwing cabs were replaced, and the narrow style front and rear railings were replaced with the wide style that NS favors. The rear pilot was modified to have a rear anticlimber and deck-mounted rear ditchlights.
About the only item on the body that makes them different from other AC44C6Ms now is the rear of the locomotive. Like the former Dash 9-40C, these units had a high-mounted sand filler. BNSF also has a tall vertical grab iron on the right side of the end. NS always went with a single horizontal drop-style grab. The other major difference is the center access door. This is not a feature that NS employed.
Another new feature that was added was brake stick holders mounted above the fuel tank on both sides.
2025-Present: Dash 9-44CW Rebuilds
The current rebuilt units saw the addition of the noticeably raised shutter system, which was added to the top of the radiator. This system has become common on ES44s, as well as on all UP, CSX, CN, and CP rebuilt units.
All 2025 units also included the brake stick holders that had previously been seen on the ex-BNSF rebuilds.
When the designs for the new tooling were made for the 2nd run of AC44C6Ms, the two newly mentioned features had not yet been added, and so the designs and tooling do not currently exist for these. These will be added in time.
ex- CEFX AC4400CW Rebuilds
Norfolk Southern acquired 36 AC4400CW from CEFX. 25 of the units were in the process of being rebuilt at Wabtec’s Fort Worth facility. Some had been painted into NS paint, and others were still in primer. They were then sold to Wabtec, which then sold them to Ferromex. They never left in NS paint, as Wabtec painted over the fresh NS paint with primer before leaving. FXE then made some slight modifications to the locomotives, such as removing the rear ditchlights. On some, they left the empty housing, and on others, they fully removed them. The units operated in primer for a few months before being painted by FXE.
There are still 11 AC4400CWs owned by NS that are currently being stored.
