Locomotives Phases - EMD GP7, GP9

These phases are based on those compiled by Scott Chatfield.

Phases - GP7

Phase 1: 1949.10 - 1950.11

• Dynamic brakes: none
• No box on walkway behind left side cab
• Solid fuel tank skirt
• Sloped pilot plates
• 86" engine room doors
• Hood straps around engine compartment: full-height

Phase 2: 1950.06 - 1953.03

• Dynamic brakes: 36" fan
• Box on walkway behind left side cab
• Slotted fuel tank skirt on units with 1200+ gallon fuel tank (after 1952.03)
• No sloped pilot plates (after 1952.07)

Phase 3: 1953.03 - 1953.12

• 82" engine room doors
• Hood straps around engine compartment: either stop at top of engine room doors (dynamic brakes) or are absent (no dynamic brakes)

Phase 4: 1954.04

• GP9 Phase 1a carbody, GP7 internals
  

From Phase 3 GP7 to Phase 1a GP9

• 2 louver groups under cab removed
• 2 louver groups added to 1st and 2nd engine room doors
• 2 louver groups removed from 4th door from long hood end
• lower louver group removed from closest door from long hood end

Phases - GP9

Phase 1a

• Handrail stanchions: fabricated pipe
• Fuel tank skirt: deep
  
• Radiator fans: 4, 36"
• Louvers under walkway in front of cab: 1 large louver group
  

Phase 1b

• Handrail stanchions: stamped channel

Phase 2

• Lower louver groups removed from generator room doors (behind cab)
• 2 louver groups added on 3rd engine room door

Phase 3a

• Fuel tank skirt: shallow
  
• Fuel filler moved forward

Phase 3b

• Louvers under walkway in front of cab: 2 small louver sets

Phase 3c

• Radiator fans: 2, 48"