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Locomotive Phases - GE Dash 9 series

The Dash 9-44CW was introduced in 1993 as a substantial evolution of the previous Dash 8-40CW. The most significant mechanical change from the Dash 8 series was the introduction of the high-adhesion "roller-blade" 3-axle truck. Much of the hood and cab remained the same, but as a result of the longer trucks, the overall length was increased from 70' 8" to 73' 2". The new truck design also required less vertical clearance, allowing for a significantly deeper underframe. The deck height was increased by 1" to 5' 11", and the standard wheel size was upped from 40" to 42".

The high-adhesion truck differed from GE's earlier "floating-bolster" (FB-3) design by the absence of the bolster and in having all the traction motors oriented in the same direction. In place of a bolster, the truck was centered using a traction pin extending down from the bottom of the underframe, and the secondary suspension consisted of four stacks of rubber pads connected directly between the truck and locomotive underframe. The truck was closely derived from the high-adhesion design used by MLW on the M-630 and M-636 some 25 years earlier; GE retained secondary suspension of the MLW design almost as-is, but extended the wheelbase and incorporated taller primary springs.

Several other cosmetic changes were made compared to the Dash 8 series. The radiator section was carried over from late Dash 8 units built with split cooling (which had thicker "wing" edges than earlier Dash 8 units) but the intakes and doors under the radiators were redesigned. The hood was lengthened around the central air intake, but the intake itself was shorter. The fuel tank received an extra bevel along the bottom edge, and the corner steps were altered to use a perpendicular (rather than angled) inner edge.

The Dash 9 series was produced alongside the very similar AC-powered AC4400CW. The most obvious visible difference between the two models was the large inverter cabinet on the left behind the cab, present on the AC4400CW but absent on the Dash 9 series. Most Dash 9 units placed the air conditioner in this location instead, as on the Dash 8-40CW. The Dash 9 also used a shorter dynamic brake hood section and a longer central air intake than the AC4400CW. More subtle differences included thicker DC traction motor cables, smaller traction motors suspended from extensions of the truck frame (instead of "dogbone" hangers on the AC4400CW) and marginally taller overall hood height above the central air intake.

Phases

These phases are of my own making. Many of the details come from earlier research I did in establishing production variations specific to Norfolk Southern Dash 9-40CW's, which are listed in a separate table below. I elected to group Phases 2c1 and 2c2 as two sub-phases since they each represent a small number of units, a few of which have inconsistent details.

The Dash 9 series underwent fewer changes than the AC4400CW, which received a gradual series of changes specific to the inverters and AC traction system. Additionally, the many changes that define Phase 2a Dash 9 production were staggered in AC4400CW production throughout 1995. (See AC4400CW phases.)

Phase 1a 1b 1c 1d 2a 2b 2c1 2c2 2d 2e 2f 2g 2h
Dates 1993-11 -
1994-03
1994-04 -
1994-05
1994-05 -
1994-12
1994-11 -
1994-12
1996-01 -
1997-05
1997-02 -
1998-02
1998-02 1998-02 -
1998-04
1998-02 -
1998-12
1998-12 -
1999-02
1999-02 -
2000-12
2000-12 -
2002-11
2003-01 -
2005-11
Truck frame Rounded extension between outer axles Smaller angled extension between outer axles, holes added between axles
Short hood top grabirons Single, angled Double, straight
Rear bottom hood intakes Small, even height Larger, variable height (taller on doors without latches)
Rear end grabirons Uneven spacing Even spacing
Air reservoir notch in fuel tank Straight Notch in middle
Fuel tank Suspended from underframe Welded as part of underframe
Corner steps Zig-zag outer edge, vertical handrail notch, steps attached to stepwell individually Sloped outer edge, vertical handrail notch, steps attached to stepwell with sheet connecting all steps No handrail notch, sloped inner edge
Axle shock struts 8 total, placed vertically inboard of brake cylinders 4 total (front right/rear left), placed at an angle outside of brake cylinders
Phase 1a 1b 1c 1d 2a 2b 2c1 2c2 2d 2e 2f 2g 2h
Roof panel above front air intake Yes No (except for first few NS Dash 9-40CW's)
Panel ahead of front air intake 1 X-panel 2 X-panels
Panel under
d/b intakesDynamic brake intakes located behind the cab on the right side
Rectangular indentation to clear hood door handle No rectangular indentation; rubber door stop added
Air reservoir pipes 90-degree connections Curved pipes
Fuel gauge Wide, recessed gauge housing Narrow gauge housing (except BNSF 4745-4747, Phase 2c2)
Dynamic brakesDynamic brakes located immediately behind the cab, with screened inlets on the right side and barred outlets on the left side
4 ridges along bottom of intakes Single ridge along bottom of intakes Narrower gaps underneath outlets
Traction motor cable brackets Early Revised spacing (group of 3 near front)
Air reservoir supports C-shaped Upside-down U-shaped
Radiator lift rings Square, with holes for flag holder Rounded, slanted
Phase 1a 1b 1c 1d 2a 2b 2c1 2c2 2d 2e 2f 2g 2h

A few notes about the parts listed in the table:

Model Variations - Dash 9-40CW (Norfolk Southern)

Norfolk Southern ordered over a thousand GE Dash 9-40CW's between early 1996 and the end of 2004. A relatively simple software change accounted for the 400-horsepower deficit compared to the standard Dash 9-44CW (4000 vs 4400 hp), and in fact NS upgraded the units to Dash 9-44CW's starting in 2013.

Externally, all Dash 9-40CW's shared the main spotting features of Phase 2a and later Dash 9-44CW production. Although there was remarkably little variation over NS Dash 9-40CW production, a whole series of very minor detail changes nonetheless resulted in almost 20 visually distinct variations (not including internal changes). I drew 13 variations in 1:36, but after discovering a few more staggered changes, I have elected to separate the 1:18 drawings into 17 variations, representing the detail changes summarized below.

For clarity, phase details that apply to Dash 9 production as a whole are repeated in this table and are highlighted in red.

  8889-
8931
8932-
8947
8948-
9008
9009-
9128
9129-
9154
9155-
9169
9170-
9258
9259-
9264
9265-
9441
9442-
9529
9530-
9534
9535-
9719
9720-
9744
9745-
9811
9812-
9841
9842-
9886
9887-
9978
Dates 1996-01 -
1996-02
1996-02 1996-02 -
1996-04
1997-02 -
1997-05
1998-02 1998-02 -
1998-03
1998-03 -
1998-10
1998-10 1999-02 -
2000-03
2000-03 -
2000-05
2000-05 2000-12 -
2001-12
2001-12 2003-01 -
2003-03
2004-03 2004-03 -
2004-05
2004-09 -
2004-12
Phase 2a 2c1 2c2 2d 2f 2g 2h
Roof panel above
front air intake
Yes No
Handrail above
walkway knuckle basket
corner
piece
Single notch-shaped rail
Angled panel behind right-side radiator intake Yes No
Walkway knuckle basket Screen Plate w/holes None
  8889-
8931
8932-
8947
8948-
9008
9009-
9128
9129-
9154
9155-
9169
9170-
9258
9259-
9264
9265-
9441
9442-
9529
9530-
9534
9535-
9719
9720-
9744
9745-
9811
9812-
9841
9842-
9886
9887-
9978
Air reservoir
pipes
90-degree
connections
Curved pipes Angled plate added
between reservoirs (~9452+)
Fuel gauge Wide, recessed
gauge housing
Narrow gauge housing,
left-side gauge moved forward
Left gauge
moved rearward
Handbrake Wheel (rear) Electric (front) Wheel +
electric
Cab Riveted
window frame
Smooth window frame,
red light added below windows
Riveted
window frame
Cab sub-base door Yes No Yes
Antennas Low-profile +
"firecracker"
Low-profile
GPS radome No Yes No Yes
  8889-
8931
8932-
8947
8948-
9008
9009-
9128
9129-
9154
9155-
9169
9170-
9258
9259-
9264
9265-
9441
9442-
9529
9530-
9534
9535-
9719
9720-
9744
9745-
9811
9812-
9841
9842-
9886
9887-
9978
Dynamic brakes 4 ridges along
bottom of intakes
Single ridge along
bottom of intakes
Narrower gaps underneath outlets
Traction motor
cable brackets
Early Revised spacing (group of 3 near front)
Air dryer Salem 975 series Both
types
Salem/GW 994 series
Air reservoir
supports
C-shaped Upside-down U-shaped
Toilet system Chemical Vacuum
(9253+)
Taller, narrower drain housing
Bell Mechanical Electronic
Radiator
lift rings
Square Rounded, slanted
Steps Straight vertical handrail notch Angled edge,
no handrail notch
  8889-
8931
8932-
8947
8948-
9008
9009-
9128
9129-
9154
9155-
9169
9170-
9258
9259-
9264
9265-
9441
9442-
9529
9530-
9534
9535-
9719
9720-
9744
9745-
9811
9812-
9841
9842-
9886
9887-
9978

References

Biel, Charles. (2018). The BNSF Photo Archive - GE C44-9W. Retrieved July 2018 from http://www.trainpix.com/bnsf/GEORIG/C44-9W/INDEX.HTM

The Diesel Shop. (2017). General Electric Dash-9s Production List. Retrieved January 2017 from https://www.thedieselshop.us/GE_Dash9.HTML

Norfolk Southern. (2006). Locomotive Equipment. Retrieved August 2015 from http://www.railfandepot.com/product/norfolk-southern-2006-diesel-locomotive-diagrams/

Toth, Chris. (2015). Norfolk Southern Diesel Locomotive Roster. Retrieved September 2015 from http://www.nsdash9.com/roster.html.

 Copyright © Michael Eby - Last updated 2018-10-31