Identifying a diesel Locomotive

Discussion in 'Railfanning Discussions' started by TSBYman, Sep 21, 2008.

  1. TSBYman

    TSBYman New Member

    I am new to railfanning and wondering How do you identify a diesel locomotive?
  2. fitz

    fitz Staff Member TrainBoard Supporter

    TSByman, welcome to Trainboard! Now, I am an old steam curmudgeon and don't know anything about diesels except what I have learned from other railfans. There are some books available, diesel spotting guides, but I have forgotten their titles. Here's what I know: Six axle EMD's are SD class, and four axle EMD's are GP class. All these new -44AC and all that other stuff I know nothing about. One of the reasons I have posted this is to arouse the diesel knowledgable people to correct me.
  3. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

    First, let me welcome you to Trainboard!

    It's good to have you here!

    The way I ID a locomotive, is first look at the cab. Is it an angular design, or of a more blocky square angles construction? General Electric (GE) widecabs tend to be angular, while Electro-Motive Division (EMD) widecabs are more blocky, using square angles. Ther are exceptions. The noses of each manufacturer for spartan cabs (the more narrow cab) look somewhat similar, with EMD noses having pointed noses, and GE noses more blocky. The hood is another spotting feature. GE and EMD hoods are somewhat similar. The radiator sections is where they differ most. GE radiators use a "wing" approach, while EMD radiators are of a flush variety, with grilles. The later-model EMDs use a flared radiator. Trucks differantiate a loco from another maker as well. EMD trucks are distinctly different from GE trucks. GE trucks on late model units use a large cast frame, with twin springs for each axle. EMD trucks do not sport the springs as visibly as the GE units' do.

    See the GE Dash 9-44CW example below; angular cab nose, winged radiators, prominent truck frames with the springs showing:


    And an EMD SD70ACe example, with flared radiators, blocky cab, radial trucks without prominent springs:


    Back in the 70's, the SD40-2 was one of the most ubiquitous locomotives around. Here's classic EMD construction from the older generation--three-hole truck sideframes, flat radiators, dynamic brakes with a "blister" and fans, pointed nose, blocky cab face, and rounded fuel tank:


    Here's an earlier GE model, a C30-7. The classic flat "pug" nose, the trucks do not have the 3-holes in the side frames, the radiator wings and angular fuel tank:


    Passenger engines are a whole 'nother story, that to come soon.
  4. TSBYman

    TSBYman New Member

    Thank you

    thank you for helping me out
  5. TSBYman

    TSBYman New Member

    So how do you identify a gp-35 from a gp-38 or 40

    Again thank you to anyone who can help
  6. Kit

    Kit TrainBoard Member

    The best way to tell the difference between the GP35, GP38, and GP40 is by looking at the fans over the radiator section at the rear of the locomotive. The GP35 has three fans over the radiator, with the middle fan being a smaller diameter. The GP 38 only has two fans over the radiator The GP 40 has three fans again, all the same diameter. The spotting differences between a GP38/GP40 and a GP38-2/GP40-2 is that on the engineers side of the locomotive; (right side facing front); on one of the doors at the front of the radiator grills, there is a water level sight glass window. Also -2 angled cabs have an angled overhang on the back of the cab.

    Hope this helps.

    And Welcome to Trainboard.
  7. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

    GP35, note the small fan between the top radiator fans:


    GP38, note the twin radiator fans, spaced closely together:


    GP40, note the 3 closely-spaced radiator fans:


    Among other differences!
  8. fitz

    fitz Staff Member TrainBoard Supporter

    Man, you guys are good. :tb-biggrin:
  9. Triplex

    Triplex TrainBoard Member

    Oh... wow. That's a huge question.

    The features mentioned for the GP35, GP38/-2 and GP40/-2 can also be used on the SD35, SD38/-2 and SD40/-2 (but there's more to those as well). There's also the GP39/-2 and the SD39. They have two fans just like the 38-series, but they don't have the raised air filter box (the hump in the roofline just behind the air intake).

    Note that the GP35 and SD35 are shorter than the GP38/39/40 and SD38/39/40. Dash 2 GPs are the same lengths as their predecessors, but Dash 2 SDs are longer than their predecessors. The above-mentioned trucks with three holes are on Dash 2s; older SDs have pairs of holes.

    SD45s look like SD40s, but with the radiators (below the rear fans) flared outward. Not as much as on the SD70ACe above, though. SD45-2s don't have the flares, and look much like SD40-2s. The three fans are more widely spaced, and the radiator is larger. There is no GP45, but there is the GP40X, which looks like a 4-axle SD45.

    GP30s look like GP35s, but they have a raised roofline on the cab and forward part of the body. You can't mistake them for anything else.
  10. Mr. Train

    Mr. Train TrainBoard Member

    Thanks to the teachers

    Welcome to trainboard then thanks to the above teachers text with photos is great so teachers carry on :shade:
  11. Triplex

    Triplex TrainBoard Member

    Since there are a lot of locomotive models, I'll ask before I go any further: Where are you, and what railroads do you regularly see?
  12. ladybngnfan

    ladybngnfan TrainBoard Member

    One old book that's really helpful and interesting is The Diesel Spotter's Guide, by Jerry Pinkepank, that was published in the seventies, the 1970s, that is. It was published by Kalmbach, the same company that publishes Trains magazine. It's also been updated several times.
  13. jagged ben

    jagged ben TrainBoard Member

    Thanks. Some of us who've been around for a while are learning some things here, too.

    And thanks Hemi for the pictures.
  14. SP 9811

    SP 9811 TrainBoard Member

    IDing tunnel motors...SD40T-2 has two fan hatches, SD45T-2 has three.



  15. SP 9811

    SP 9811 TrainBoard Member

    SD45's or "Flare45", has a flared radiator section. In this shot, the point, second and forth units are SD45's, compare them to the tunnel motor, the third unit.
  16. Triplex

    Triplex TrainBoard Member

    GE 6-axles, 1988-2004, briefly:

    C40-8: All angles, unlike earlier GEs. Trucks similar to C30-7 and other older GEs.

    C40-8W: Same, wide nose.

    C44-8W: Same, slightly thicker radiator wings. Only CSX has this model.

    C40-9W: Similar to C44-8W, "rollerblade" trucks (like C44-9W picture on previous page).

    C40-9: As C40-9, standard nose. Only NS has this model.

    C44-9W: As C40-9W, nose headlight.

    AC4400CW: Similar to C44-9W, inverter cabinet (large structure behind cab on left side). Many have self-steering trucks.

    AC6000CW: Similar to AC4400CW, but longer. Radiator section overhangs at rear. Same choice of trucks.

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