Locomotive Phases - EMD SD20
The SD20 is an Illinois Central rebuild of older SD-series locomotives, including the SD7, SD24, SD24B and SD35. The phases below are for the SD20 rebuilds themselves (excluding those rebuilt from SD35s) and do not reflect the phases of the original locomotives prior to rebuilding.
These phases are of my own making. I have grouped together three variations as Phase 3a, 3b and 3c (rather than 3, 4 and 5) because Phases 3a and 3b account for only three locomotives.
Phase 1: IC 2000-2011
- Right side air pipe: extends to behind rear jacking pad
- Cab side: flat
- Short hood: extends to original SD7/SD24 hood end
- Step guards ahead of battery boxes: short
- Battery box and cab sub-base doors: hinged
Phase 2: IC 2012-2023
- Right side air pipe: extends to rear of fuel tank
- Cab side: bolted rectangular panel around window
Phase 3a: IC 2024
- Short hood: extends to pilot plate
Phase 3b: IC 2025-2026
- Step guards ahead of battery boxes: long
- Results in more steeply sloped corner handrail
Phase 3c: IC 2027-2037
- Battery box and cab sub-base doors: lift-off tabs
- Units may have either round-top fans (as on the original EMD SD24) or flat-top fans (as on second-generation EMD units).
- Two units (IC 2026 and 2030) used a square wire grid over the radiator intakes rather than chickenwire.