I’ve been studying the cab differences between the EMD’s and GE’s, mostly so I can tell at a distance or when they fly past at crossings. So correct me if I’m wrong:
GE’s have a more pointed/slopped hood, windows are square, headlights on the nose.
EMD’s have a more squared, flat hood, tear-drop windows and the headlights are above the windows.
I was also told the cooling system on one is larger, but they both appear to have fins towards the rear.
It’s worse than that. There are now several styles of replacement cab, and you have to know them separately from the ‘factory’ appearance.
Your best bet, as noticed, is to study field guides and photo references to figure out what your favorite ‘spotting features’ are and then use them. A reasonably good ‘quick’ one, in my opinion, is trucks: no EMD has either the ‘rollerblade’ or the outside-beam steerable trucks, and no GE has HTCR radials, leaving any overlap in the older-locomotive families where a quick study of Flexicoil, Dofasco, etc. will be all you need.
CN ordered GE Dash-9’s and some ES44DC’s with teardrop windows.
The best way to tell the two apart is their sound. The GE engines (4-stroke) rattle at idle and have a prounounced chug when working hard. EMD engines (2-stroke) sound very smooth, and roar like a jet when revved up.
This does not work for the Tier-IV engines, both designs sound very similar, like a GE but with a lot of muffled whooshing.
GE’s are pretty consistent the last decade or two:
The big radiators are the most prominent identifiers. They are high up and kinda look like they are set on top of the rear of the body and more or less aquared off on the ends. The hood in front of the cab is sloped like the roof of a house. The fuel tanks have a flat vertical surface on the upper side and have flat angled facets on the lower area. On the right side the fuel tank has a large “cut out” area where the air tanks (I think) are set in.
EMD’s have several variations in appearance:
Older EMD’s have vertical radiators flush with the body. Later ones have the radiators angled out from the body, and they are not as high up as the GE’s, also, on the latest ones they are not all the way back on the body. The hoods on the older cabs are horizontal in the middle with bevels on each side. These have the teardrop windshields. The newer ones have a stepped hood and rectangular windshields, though I vaguely remember something about going back to the teardrop windshields. (Somebody correct me if not.) The fuel tanks have a gentle cardioid-shaped curve on the sides, but I noticed that the newest ones approximate this curve with a series of facets.
I find you can still tell the difference; even the 1010 4-stroke has a reasonably even firing order, whereas the GEVOs maintain the master-rod slight offset. For the upgraded 710s the difference in timbre and rhythm is still very distinctive. (Interestingly in an age of more and more implied muffling/silencing, one of the great sonic delights remains the big Polish-block 710s in some of New Jersey Transit’s later locomotives…)
I also find that most EMDs have a pronounced whine in their sound, compared to any of the GE FDL/GEVO family.
I’m still learning the differences for the C175 and QSK families, and probably will be for some time yet.
Most of the major roads paint the model number near the front. Just be aware this is road specific and may be different between railroads and the builder.
The new “Teardrop” windshields on the Tier 4 EMD locomotives are subtly different with the teardrop portion being less pointed.
If you don’t want to spend money on a Field Guide you could visit this website and one-by-one selecct each model of locomotive, select a good up-close view and study it.