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 an all-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 couple of phases (2d through 2f) account for roughly half of the total production.
These phases are of my own making.
Rear hood and radiators
|Rear hood doors/vents||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)||(1)||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|
|Middle hood panels under aftercooler||Square latched panel next to small bolted panel; fastened to hood door underneath on engineer's 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 conductor's side|
|Front upper hood panel under aftercooler||Latched on engineer's side, bolted on conductor's side||Bolted on both sides||Extended rearward slightly on conductor's side (appeared on late Phase 2d2 units)|
|Aftercooler||Flush rooftop grill||Raised rooftop box||Longer wing section, revised angled section under wing||Flush rooftop grill|
|Radiator roof grills||Flush||Raised, shorter wing section|
|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|
|Rear hood end||Vertical headlight (several forms), end door||Horizontal headlight, no door|
Front hood and underframe
|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 conductor's 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 conductor's side cab panel||Rib along top||4 bolts along top (inconsistent in Phase 1e through 1f)|
|AC Dynamic brake outlets (2 vents)||2nd and 3rd openings||1st and 3rd openings|
Small grill between vents
|Latched panel between vents (2)|
|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|
|DC Dynamic brake intakes||Hinges on left side; intakes in 1st and 3rd large panels||Hinges on right side (inconsistent in Phase 2c)|
|Handrails||3rd, 4th and 5th stanchions from rear moved rearward on left side||4th stanchion from rear moved forward on left side||Thicker handrail stanchions with wire loops||Rearmost 2 stanchions swapped (wide/narrow)|
|Short hood||Rounded corners, door on conductor's side; no headlight notch on short hood with cab-mounted headlight||Headlight notch, with or without headlight||Angular corners, door on engineer's side, thicker door hinges|
|Anticlimber||Angled braces underneath||No angled braces|
|Trucks||Welded plate handbrake chain bracket||Curved handbrake chain bracket||Modified truck casting (3)|
- 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
- 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 (conductor's side up to Phase 2c, engineer's 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.