What makes a second generation diesel second generation? What locomotive(s) are regarded as the first of the second generation? Where does the GE U25 fit into the picture? I haven't been able to find anything on the web that casts much light on these questions.
Second generation means that they replaced other diesels, not steam. The first definition I ever heard made the GP20 and SD24 the first second generation diesels. I'm not sure when the second generation is considered to end.
Would that make -2s third gen with GP/SD50/60s, SD70s and ACs fourth gen and GEVO/gensets fifth gen??
I've never heard of more than four generations, but I'm not sure where they divide. The issue is that, unlike steam, diesels of a given era aren't categorically retired at once. For example, some Dash 2s and Dash 7s delivered around 1980 were replacing F-units and other first-gen power... others were replacing Centuries and early U-boats.
Generally speaking, a second Generation diesel is generally considered to be 645 engine block. IE the second generation of the EMD engine block. However, GP 30s and 35s are generally also considered Second Gen by most. This also makes sense in many ways. The 30/35 was a completely different platform. The GP20 was of course the first Turbo'd unit, but it doesn't really fit with the rest of the second gen. So, Second Gen would run generally 30-40-2. Gen 3 is roughly superseries 50 and 60 and perhaps early 70s series. GE was a gen behind, so there is no doubt that in terms of timing it's a second gen unit, but of course, based on sales volume, nobody cares about any GE products till the 80s and gen 3.
The way that I've always heard it is that a "Second Generation" unit (specifically "road units" and not "switchers") are defined as having a "sealed car body" and that they were marketed to replace other diesel locomotives. This places locomotives like the U25 (GE), GP30 (EMD), and ALCo's "Century Series" into the "Second Generation" and locomotives like EMD's GP20/SD24 and ALCo's RS series into the "First Generation". So, what is a "sealed car body"? The simple answer here is that it is one where the car body is complete sealed. :wink3: The more complecated answer actually deals with how air is either drawn into the car body ("First Generation") through filters on the car body access doors or is pressurized and forced through the car body from a central point ("Second Generation")...Outside in verses inside out.
Clearly this is a confusing issue. The whole idea of first generation, second generation and so on was actually thought up by some railfan. I don't believe you will find the rails worrying to much about first, second and so on. To add to the confusion locomotives went through various rebuilds that railfans picked up on and started calling them "Phase 1" and etc. The rails simply looked at them as rebuilds. If you want to get technical the first Diesels to arrive on railroad property were small switchers from FM, Baldwin and others. Second to arrive the F type units, "Covered Wagons", a railfan nick. I won't repeat what the rails called the early F type units but the F designation, should give you a hint. Third to arrive the GP 7's and GP 9's with some odd ball GE and FM Units tossed in for good measure. Fourth to arrive as railroads traded in the F units were the GP 20's and GP 30's along with new power on six axles the SD 7's, 9's and 24's. These were followed by...ok I quit. The point is useless, mute, unless you draw a date line or some sort of horse power limit you are stuck with wondering where the first generation dropped off and the second started and the third and the fourth and the fifth....etc. It would be like trying to decide when the first generation, automobiles dropped off and the second started. I don't believe I've ever heard a car buff refer to autos in the first generation and etc.. It's more about horse power, type of engine and transmission, the generator and/or first alternator. Type of manifold, carburetor, drum brakes and who built the car. I wouldn't give this much thought unless you are trying to impress your fellow railfans. I prefer to stick with the rails and call them what they are. A GP20, GP30 and leave off the "Phase" or "First Generation". When rebuilt call them a rebuilt unit. Santa Fe had their own designation for rebuilds feel free to use them. Rather futile subject in my opinion. I have enough trouble keeping track of delivery dates and duration of the locomotives, the horse power and tractive effort. I think that's enough to worry about. I need to go out and run my Phase Five train layout... Grin! Have fun!
Here's a question for you. Have you ever been invited up in the cab of a locomotive? Did you ask the crew what type of locomotive they were in? Bet, I can guess the answer. Let's see it probably sounded something like this, "I don't know it's just a locomotive that gets us from point A to point B and back". Am I right? Heck, the majority of rails don't even care about what they are operating, as much as getting back home at the end of the shift. This prompts the question. If they aren't worried about all these issues then why are we? Ah shucks this is just a hobby anyway. Besides it's fun to have everything pigeon holed, sliced and diced. Fun is what fun is and comes in many packages. Simply enjoy your hobby however you wish to pursue it. Have fun! Rule #!.
There are two schools of thought on what constitutes the second generation of diesel locomotives. There is the Mechanical School and the Operational School. Both are correct, but I would say that the Mechanical School predates the Operational School. Also the use of this term "second generation" dates back to the early 1960s and may likely have originated with then Trains Editor David P. Morgan. It is certainly used in his Diesels West book on the dieselization of the Burlington from 1963. Since we are all just sounding off here I thought about something I wrote a couple of years ago for my train club newspaper. Called the story "My Generation". Here is a paragraph about UP and EMD's early experimentation with turbocharging the 567 engine. "Experiments in turbocharging the EMD 567 series engine were begun by Union Pacific in late 1955. Union Pacific wanted to increase the operational efficiency of its locomotive fleet. Four GP9s were turbocharged in the East Los Angeles Shops of UP. Another 15 GP9 and GP9B units were outfitted with turbochargers by UP. This UP program of experimentation led directly to EMD’s first attempts to turbocharge the 567. This effort by EMD led to the SD24 demonstrator #5579 that first breathed turbocharged air in July of 1958. This demonstrator actually featured a centralized air intake, but this was not carried over to production units. Union Pacific offered another nine of its GP9s as test units for the EMD turbocharger experiments in the Spring of 1959. The first production SD24s rolled off the assembly line for the Burlington and the Santa Fe in May of 1959. The first production GP20 was built for the Western Pacific in November 1959. These machines are considered first generation by most diesel historians, but in operational practice they replaced older first generation units. They could be called Generation 1.9 as they were so late in the first generation. Alco now had some competition for its turbocharged 251 line of diesel locomotives." Hope this helps answer your question.
In my previous post I mentioned the two schools of thought on what defines the second generation of dieselization. The Mechanical School identifies the GE U25B as the first Second Generation machine. It is second generation because it is a high horsepower with a central air intake to distribute clean air to the inside of the hood and has a sealed hood. This was the first machine to have all of these features in one package. The U25B built first in 1959 as the XP24 and was the first machine to have these features and set the railroad industry in a buzz when it was announced as the U25B, a domestic GE locomotive. The other diesel builders perceived that they were behind in design and had to catch up with GE on these features.
Taz you are the man. This is the Mechanical School definition of what the Second Generation is. EMD experimented with a central air intake on the SD24 Demonstrator #5579, but removed it. I don't think EMD had the sealed carbody idea yet when the first SD24 was built in July 1958.
John: I consider the EMD Dash Two Line as Generation 2.5 or 2.6. Somewhere along those lines. You can see how I approach this bit of history.
I went a bit further in classification of the Generations. The first generation starts with the first diesel locomotive in about 1918. It was not a successful unit, but that is where you start. I took the first generation starting in 1918 and lasting into the late 1950s or early 60s depending on how you look at it and subdivided it into smaller parts. A forty year first generation just does not make any sense to me. I called the early part of this first generation "Generation Zero" or the "Experimental Generation" After this so-called Generation Zero you have a new later part of the First Generation I call the Production Generation. You can easily trace the first production assembly lines set up by the old steam builders and the new General Motors facility in Illinois starting in the 1930s. Mass production of diesel locomotives started with General Motors at McCook, Illinois in 1936, was interrupted by World War 2 and quickly recovered to greater levels after the war. In my opinion the generations overlap somewhat. You don't have to take any of this stuff seriously it's just revisionist history.
Amen Brother!!! The information on "phases" and "generations" is all good stuff although just about everything about it is an invention of folks not directly connected with the manufacture or the use of the locomotives. As BarstowRick said, "...it's fun to have everything pigeon holed, sliced and diced." and "phases" and "generations" help to do just that...
Folks , Indian 2nd Generation diesel engine WDM is good in hauling at a speed of 140km. Indian Diesel engines more attractive than any other in the World. Sukumaran. ------------------------------ Blaze Infotech
