Locomotive Phases - GE C32-8, C39-8
The first Dash-8 units were introduced by GE in 1984 and were produced alongside the last Dash-7 units. Eighteen initial demonstrators were produced: Three B32-8's for BN, three B39-8's for ATSF, ten C32-8's for CR and two C39-8's for NS. Dozens of additional C39-8's were built during the next two years for CR and NS, but no more B32-8's, B39-8's or C32-8's were built before GE introduced a much-improved "enhanced" version of the Dash-8 series in 1987, which accounted for the vast majority of Dash-8 production.
Early (pre-1987) Dash-8 units carried over some spotting features of the Dash-7 series, such as the general style of the hood doors and a break in the hood width near the radiators, along with a second break in the hood width on the fireman's side closer to the front of the hood. Although it had higher eaves, the cab still had a rounded roof and was the same height as on Dash-7 units (105" above the frame, with the same 75" frame height). The hood behind the cab created a "hump" that was taller than the cab itself, and the radiator intakes were vertical and located under angular radiator "wings". The raised hood section behind the cab contained a boxy housing for the dynamic brakes, which had been incorporated into some B30-7A and C36-7 units a few years earlier.
The C32-8 was 2' 9" shorter (67' 11") than the C39-8 (70' 8"), with length removed in the fuel tank and the center section of the hood. As with earlier GE units, the C32-8 had 6 engine room doors per side (indicative of the 12-cylinder engine) while the C39-8 had 8 doors per side. The ten CR demonstrators were the only C32-8's built.
These detail differences are largely based on my own observations and research, and they follow the same pattern as for the GE B32-8 and B39-8. I have attempted to match them to existing phase descriptions I've been able to find from online sources, while filling in many additional details. With the exception of NS 8664-8688 (often labelled "C39-8E") all C39-8 production used the early Dash-8 carbody described in these phases.
|Numbers||NS 8550-8551||NS 8552-8563|
|NS 8564-8613||NS 8614-8638||CR 6000-6021|
|Dynamic brake housing||Ridge along the top||Revised design, no ridge along the top, larger hinged panels on the engineer's side|
|Handrail stanchions||4 evenly spaced stanchions at the rear; 10 stanchions on fireman's side and 12 on engineer's side||Unevenly spaced stanchions at the rear; 12 stanchions on fireman's side and 13 on engineer's side on C39-8 (1 fewer per side on C32-8)|
|Front hood section||Additional bolts added to hood panels behind the cab on the fireman's side|
|Short hood||Seam down the middle of the front, blank headlight housing, ratchet hand brake, rectangular top vent||No seam down the middle of the front, wheel hand brake, circular top vent||No blank headlight housing|
|Radiator wings||3 hinges along the side panels||5 hinges along the side panels|
|Hood ends||Grabirons attached to thin metal strips on top of the hood; no "X" panels on the angled corner sheets||Grabirons attached directly to the hood; "X" panels added on the angled corner sheets|
|Jacking pads||Covered at the front, exposed and rectangular at the rear, horizontal ridge in the middle||Covered at the front, angular cover at the rear, horizontal ridge in the middle (as on most Dash-7 units)||Jacking pads: Exposed and rectangular at front and rear, no horizontal ridge in the middle (as on later Dash-8 units)|
|Brake chain pipe||curved||straight|
|Rear intakes||Surface-mounted, rectangular outer frame||Flush, no outer frame; no small intake on the upper panel under the front of the radiator wings; fewer bolts on the radiator intakes; rear radiator intake divided into 1 large + 1 small intake|
|Cab doors and hood door behind the cab||Round corners||Square corners, lowered latch on hood door|
|Truck sand brackets||L-shaped angled sheet (as on late Dash-7 units)||Square tube welded to small flat plate (as on later Dash-8 units)|
|Truck brake slack adjusters||Trapezoidal plate with offset holes at the ends||Square tube with inner adjustment holes (appeared on late Phase 2 units)|
Later NS C39-8's (8564 and up) were built with higher-capacity dynamic brakes that used three vents instead of two. This design was not adopted for later Dash-8 or Dash-9 models, and triple dynamic brake vents didn't appear again until the AC4400CW several years later. Additionally, NS 8564 and up and all CR C39-8's used a larger fuel tank than earlier units, which used the same size tank as on the C32-8. CR C32-8's and C39-8's featured a front anticlimber; NS C39-8's did not.
Most versions used a mix of Adirondack and GSC-style truck castings. Rockwell International assumed the FB-3 design previously cast by GSC, and it was later adopted by Atchison Casting upon their acquisition of Rockwell. This version of the FB-3 varied little across the foundries, and it can be identified by holes centered between the axles and smoothly curved side frame edges. FB-3 trucks cast by Adirondack had holes closer to the outboard axles and a squarer side frame contour. As Adirondack went out of business in 1987, few later Dash-8 units were built with Adirondack trucks.
In addition to production variations and typical 1990s updates (such as the addition of ditch lights) NS versions had the original bolted panel at the left rear of the hood replaced by two doors some time after they entered service. NS also revised the rooftop radiator grills on both their own units and on units inherited from Conrail. Many NS units had the original Airchime K5H replaced with a P5 or K5LA.
Transition: Early to "Enhanced"
After the first Dash-8 units were produced, GE made a large number of mechanical and electrical improvements that appeared in the last order of C39-8's in 1987, as well as in all production versions of the similar B32-8 and B39-8. Although these upgraded versions commonly have an "E" added at the end of the name (especially the C39-8E, to differentiate it from earlier production) the builder's plate apparently lacked such a designation. NS 8664-8688 was the only order of "enhanced" C39-8's, and they are sometimes regarded as a "Phase 4" C39-8. Most rode on Adirondack truck castings.
Externally, all later Dash-8 units had an almost entirely redesigned carbody, which included the following changes:
- The cab roof was changed to an angled design and raised to match the hood, while the headlight/numberboard assembly was narrowed and had the headlights mounted horizontally
- The dynamic brake/central air intake area was simplified, with fewer doors and seams
- The hood was made the same width along its entire length, eliminating the break in the hood width near the radiators
- Hood doors received recessed hinges and gaps between the doors, instead of surface-mounted hinges and overlapping door panels
- Standard upper and lower door latches replaced the previous GE-specific central door handles, and the central doors were shorter in height
- The radiator intakes were angled, allowing for a single large fan in place of two smaller ones
- The hood doors and intakes under the radiators were lined up
- The rear hood end received a shallower taper and vertically mounted headlights
As part of GE marketing, locomotive model names were changed around late 1987 to have "Dash 8" spelled out. This coincided with an increase from 3900 to 4000 horsepower for the 16-cylinder versions, so there was therefore no such thing as a "Dash 8-39B" or "Dash 8-39C". Cosmetically and mechanically, the 4000-horsepower units were an incremental evolution from the last 3900-horsepower units, with only a few visible external changes separating the C39-8E from the Dash 8-40C:
- Longer fuel tank
- Air reservoirs moved from the ends of fuel tank to a notch in the right side of the fuel tank
- Six bolted rectangular panels on the radiator wings (four on the edges, two underneath) instead of four wraparound hinged panels
- Door latches positioned lower on the cab sub-base on the engineer's side
See the Dash 8-40C and Dash 8-40CW phases for subsequent GE Dash-8 changes.
Atlas Model Railroad Forums. (2008). Chances for a C39-8? Messages posted to http://forum.atlasrr.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=47108&whichpage=1
Conrail. (1989). Locomotive Diagrams. Retrieved February 2013 from http://rr-fallenflags.org/cr/cr-lb89.html
General Electric. (1984). Series-8 Handbook. Retrieved September 2012 from http://rr-fallenflags.org/manual/d8-hdbk.pdf
General Electric. (1987). Operating Manual, 1987 Series-8 Diesel-Electric Locomotive. Retrieved January 2015 from http://www.rr-fallenflags.org/manual/D8-OM.pdf
Strack, D. (1997). Union Pacific GE Dash 8 Locomotives. Retrieved December 2014 from http://utahrails.net/articles/up-dash8.php.
The Diesel Shop. (2011). General Electric Six-Axle Dash-8s. Retrieved January 2015 from http://www.thedieselshop.us/GE_Dash8C.HTML.
Trainorders.com. (2007). GE C39-8. Messages posted to http://www.trainorders.com/discussion/read.php?3,1450197