First is the F units, (both A & B). You had FT's F3's, F7's, and F9's. I decribe below, it is hard to tell the early F units apart because of all the changes that were constantly happening, I am not goning to get into all the nity gritty, just give basics. Here are a F unit, A & B.
Brian M Frierdich
Next up we have the GP7/9/18. While there are diffrences, they basicly look the same. In fact it was (and to some degree, still is, common pratice to have Phases of locomotives). It is because of these Phases, that it gets hard to tell a GP7, from a GP9, from a GP18. As time went along and new peices came out, GP7's started getting upgraded parts, soon to be introduced on the GP9's and such. Therefore it becomes hard to tell the diffrences. But here is what a basic GP7/9/18 looks like. Notice that it has the high short hood end (altough through rebuilding, most have been choped nosed), and they eather have 2 big raidatior fans (as on the RA loco), or 2 sets of 2 smaller fans (as on the ACL). Also notice the raidator intake screens, one at the end of the long hood (top) and one behind the cab one is a set of 3 the other a set of 2. Those and the fact that they look so small are the easy ways to tell them. There are more specifics, but I am just nameing the basics to tell easly.
The next major locomotive model to be produced, is the GP30. This is by far the easest loco to identify, the large top blister covering the cab all the way back to the dynamic brake's is what gives it away. These were also buil as B units. Other forms of the GP30 still exist today, most comminly, in CSXT road slugs, and BNSF GP339M's, E's, and V's, re built from GP30 bodies. Here is a GP30.
In case you were wondering, the Dynamic Break, on the GP's is the bulge in the middle of the long hood, at the top, on units.
Next up was the GP35. This is the model where EMD started to standardise the basic body, it is identifyed by the rear raidator fans easyest. You will notice that there is one big fan, followed by a smaller fan in the middle, and then another big fan behind.
Then came along the GP40's the best spotting feature of these locos, are the three big raidator fans on the rear.
Up next is the GP38. Altough looking like a GP40, is is distingushed by the 2 radiator fans on the back.
The best ways to figure out if it is a -2, is a overhang on the back of the cab on top, and a water level sight glass. Here is a photo of a -2 to see. You can see the water sight glass, just in front of the rear raidator fan, (partitaly in the maroon stripe), and also you can kind of make out the overhang on the side of the cab.
Canadian National is the only railroad to order GP40-2LW's wide cab GP40-2's and also GP38-2W's
Here is a CN GP40-2LW now owned by the Central Michigan. (Quite a few of the GP40-2LW's have been sold to other companies).
Up next is the GP50. Its best spotting feature, is the large raidator section. Notice it is quite a bit taller, than any of the other ones so far. And also it has 3 fans. Also these were the last units to use the rounded blower housing, (the round top bulge, behind the cab, on the FURX unit0 as the 60's have angled ones. Also BNSF had some GP50's with the new blower housing. Also starting with the 50's they had a rounded anticlimber, on the ends of the unit (can be seen in the overhead photo of the CNW unit, see how the end of the walkways are rounded and thick).
Jack Welshiemer
Well this brings us to the last 4 axle unit produced so far by EMD. The GP60. The GP60's differ from the 50's by two pronounced features. One is the traction motor blower housing that I talked about at the end of the 50's (you can see it behind the cab on the NS unit), and the other is the dynamic brake housing is verry verry square looking (you can see this better in the photos of the BNSF unit). Also you had the GP60M. These are the only wide cab 4 axle unit from EMD. Also in this series are the last as of yet built, B unit cabless units, all built for the Santa Fe and now on the BNSF. Here is a GP60' GP60M and a GP60B.
Nathan D Holmes
Next we will look at GE 4 axle units.
