Locomotive Phases - GE ES Series
The GE Evolution series was first introduced in 2002 to meet Tier 2 emissions standards that took effect in the beginning of 2005. In contrast to EMD's SD70ACe and SD70M-2, which combined existing mechanical and electrical components with a largely new frame and carbody, the GE ES series introduced a new 12-cylinder engine (the GEVO, derived from the previous HDL) while retaining the frame, cab and front hood section of the AC4400CW. By the end of 2015, thousands of ES locomotives had been built in three main model series - DC (ES40DC, ES44DC), 6-motor AC (ES44AC) and 4-motor AC (ES44C4).
Unlike the previous Dash-9 series, the ES40DC and ES44DC retained the large cabinet behind the cab on the left side that would otherwise house the inverters on AC units. The ES44C4 was a variation of the ES44AC with the middle traction motor in each truck removed, giving an A1A-A1A wheel arrangement. It employed a mechanism above the center axle powered by air cylinders that lifted the axle slighly at low speeds, transferring a small portion of additional weight onto the powered outer axles for greater adhesion.
The biggest change in ES series production occurred with the revised radiators and rear hood section beginning with Phase 2a starting around early 2007. Most other detail changes were relatively minor, and the last few phases (2d through 2f) account for roughly half of the total production.
These phases are of my own making. "Left" and "right" sides refer to the conductor's and engineer's sides, respectively.
|Rear hood doors/vents|| |
(1)Rear hood doors/vents, Phase 1a: 2 small horizonal rectangular vents in bolted panel, flush doors (3 on left, 3+3 on right)
|1 large vertical rectangular vent in bolted panel, same doors||Raised doors with beveled edges (3+2 on left, 3+2+3 on right)|| |
(2)Rear hood doors/vents, Phase 2d1: Same as Phase 2d2 and later except for tall intake on the 5th door from the rear of the hood on the right side (intake is shorter on later units)
|2+3 on left, revised spacing/grill height on right|
|Rooftop panels near aftercooler||2+3 hinges||2+1 hinges (2 hinges on some Phase 1b)||No hinges|
|Radiator intakes||Single screened panel, narrow vertical bar behind screen||Two screened panels, vertical bar between panels||Shorter intake on right, revised panel ahead of intake|
|Middle hood panels under aftercooler||Square latched panel next to small bolted panel; fastened to hood door underneath on right side||2 hinged latched panels, square intake, angled forward edge; not fastened to hood door underneath||No square intake||Vertical forward edge; small bolted rectangular panel added on left side|
|Fuel filler mounts||Rectangular; rear mount absent unless fuel filler present||Round||Rear mount present with or without fuel filler|
|Front inverter cabinet panel (AC versions)||14 bolts, no hinges||12 bolts, 2 hinges on right side|
|Hood side grabirons||6 grabirons on left side||None|
|Walkway side frame||Hinged panel ahead of left rear jacking pad||No hinged panel (inconsistent in Phase 1c2)|
|Sand line brackets||Attached to truck frame||Attached to lower suspension assembly (late Phase 1e)|
|Lower left side cab panel||Rib along top||4 bolts along top (inconsistent in Phase 1e through 1f)|
|Aftercooler||Flush rooftop grill||Raised rooftop box||Longer wing section, revised angled section under wing||Flush rooftop grill|
|AC Dynamic brake outlets (2 vents)||2nd and 3rd openings||1st and 3rd openings|
Small grill between vents
|Latched panel between vents |
(3)AC Dynamic brake outlets: Some Phase 2e and later AC units with 2 vents reverted to the 2nd and 3rd openings as on earlier phases
|AC Dynamic brake intakes (2 vents)||Hinges on left side; intakes in 2nd and 3rd large panels||Hinges on right side (inconsistent up to Phase 2b); intakes in small panel and 2nd large panel; narrower bars behind screens|
|Front upper hood panel under aftercooler||Latched on right side, bolted on left side||Bolted on both sides||Extended rearward slightly on left side (appeared on late Phase 2d2 units)|
|Radiator roof grills||Flush||Raised, shorter wing section|
|Handrails||Narrow stanchions with sheetmetal clamps|
Thin rails at corners inserted into thick rails along side
|3rd, 4th and 5th stanchions from rear moved rearward on left side||4th stanchion from rear moved forward on left side||Larger handrail stanchions with wire loops||Rearmost 2 stanchions swapped (wide/narrow), all rails thin|
|Rear hood end||Vertical headlight (several forms), end door||Horizontal headlight, no door|
|DC Dynamic brake intakes||Hinges on left side; intakes in 1st and 3rd large panels||Hinges on right side (inconsistent in Phase 2c)|
|Short hood||Rounded corners, door on left side; no headlight notch on short hood with cab-mounted headlight||Headlight notch, with or without headlight||Angular corners, door on right side, thicker door hinges|
|Anticlimber||Angled braces underneath||No angled braces|
|Trucks||Welded plate handbrake chain bracket||Curved handbrake chain bracket||Modified truck casting |
(4)Trucks, late Phase 2e: Flat sections were cast into the Hi-Ad truck frame casting to attach the ES44C4 axle lifting mechanism; after late 2010 these flat areas were present (without the mechanism) on other models
|Center hood doors||Latches on 1st and 5th doors (left side) or 1st and 4th doors (right side); latch on rear door under exhaust stack (left side)||Latches on 1st and 4th doors (both sides)||Revised latch locations |
(5)Center hood doors, Phase 2g: Latches on 2nd and 5th hood doors with flipped door widths (both sides); latch on middle door under exhaust stack (left side)
- Rear hood doors/vents, Phase 1a: 2 small horizonal rectangular vents in bolted panel, flush doors (3 on left, 3+3 on right)
- Rear hood doors/vents, Phase 2d1: Same as Phase 2d2 and later except for tall intake on the 5th door from the rear of the hood on the right side (intake is shorter on later units)
- AC Dynamic brake outlets: Some Phase 2e and later AC units with 2 vents reverted to the 2nd and 3rd openings as on earlier phases
- Trucks, late Phase 2e: Flat sections were cast into the Hi-Ad truck frame casting to attach the ES44C4 axle lifting mechanism; after late 2010 these flat areas were present (without the mechanism) on other models
- Center hood doors, Phase 2g: Latches on 2nd and 5th hood doors with flipped door widths (both sides); latch on middle door under exhaust stack (left side)
- Versions with steeply sloped end handrails (rather than more slanted zig-zag handrails) have an additional grabiron on the bottom front of the short hood beside the cab door (left side up to Phase 2c, right side on Phase 2d and 2e).
- CP 8825-8839 are early Phase 2a1 units with unique bolted intakes under the radiators and pre-Phase 1g dynamic brake vents.
- Numberboards and headlight can be cab- or nose-mounted.
- Trucks: Hi-Ad on DC versions; Hi-Ad or radial-steering on AC versions.
- AC versions have thinner traction motor power cables, and larger traction motors suspended by hangers rather than resting on a section of the truck frame.