The April 2024 MR - already available in the archives - has a piece by Jeff Wilson about diesel locomotives and what generation they fall into. I'm not going to repeat the table from the article, but I am going to pick it apart a bit, so spoilers...
My take on the generations differ from Jeff's largely on where the boundries are drawn. He groups a century of locomotive development in to 4 generations, I feel there's more like 6 or 7.
Broadly speaking, 1st generation runs from the proto-diesels of the 1910s and 1920s, through the early switchers and road locomotives of the 1930s, WWII era, and early 1950s. These are the diesels that displaced steam.
Generation 2: the horsepower race era of the late 1950s and the 1960s. These are the diesels that killed off steam and began to displace 1st generation diesels. This starts with RS27 and RS32 for ALCO, the GP30 for EMD, and the surfacing of GE's U-boats.
Generation 3: this is Dash-2, Dash-7, and Dash-8 era, into the EMD 50 / 60 series. ALCO is dead (but not buried) and it's just EMD vs GE.
Generation 4: this is the second horsepower race, with the 70, 80, and 90 serieses from EMD and the ***?! model names from GE. The wide nose diesel becomes standard.
Generation 5: this is the AC revolution or the MAC Attack, if you prefer. EMD vs GE is becoming a fight to the death.
Generation 6: is the current generation of enviromentally "friendly" GEVOS, EVOS, and Gensets. GE has replaced EMD as the #1 builder, though both companies aren't who they once were.
Generation 7: is not really here yet, but it's hinted at by battery-electric test locomotives. I doubt it will be an all alternate fuels generation, but I also don't think it is going to be wholly diesel either.
AJK
Can the OP provide rationale for the various generations? What is the OP's knowledge based on and what are his sources? Before a legitimate discussion happens, I'd like to know what is the OP's background.
The generations used by Jeff were not created by him, but are the common breakdown used by prototype rail historians. And it was established a good while back, so admittedly it could likely use some updating especially regarding more modern stuff.
But I have no horse in this race, I model 1954, so all I have is "first generation" diesels. The newest locos on my layout are two EMD SD9's fresh from LaGrange.
The common definition of "second generation" are diesels that were purchased to replace diesels - that would be the early diesels.
Nearly all the Class One railroads were effectively dieselized by 1955/56 and the diesels bought from the mid 50's to the early 60's were effectively just improved version of the earlier stuff.
Fresh designs, introduced to replace earlier diesels, starting in the early to mid 60's are what most consider "2nd Generation".
Despite increases in hp, an EMD F9 is just an upgraded F3 and the SD9 is just an SD7 fixed to make it effective at its job.
Real advancement at EMD came with the GP18, GP30/35 and the GP40.
But again, in my little world they don't exist.
And as for that stuff on the rails today, I don't even have the interest to learn about them......
So I will leave this to the rest of you.
Sheldon
And how does this fit with the Hatton's concept of eras? Since they're (1) British and (2) Defunct, does this even matter for American railroading? I don’t know. I'm old enough that everything went from steam to Transition Era, and after that Modern Era. My own layout never made it to the Modern Era.
I suppose we should consider every idea, though. The model railroading community probably has as much expertise in railroading through the ages as anyone.
It takes an iron man to play with a toy iron horse.
MisterBeasley And how does this fit with the Hatton's concept of eras? Since they're (1) British and (2) Defunct, does this even matter for American railroading? I don’t know. I'm old enough that everything went from steam to Transition Era, and after that Modern Era. My own layout never made it to the Modern Era. I suppose we should consider every idea, though. The model railroading community probably has as much expertise in railroading through the ages as anyone.
As I explained, this is not a classification system setup strictly for modeling. It was defined years ago by those studing the history of the prototype, and used by modelers as a "general reference".
In Europe most railroads have been run by the respective governments for a long time, increasing the amount of standardization and limiting the number of types of cars and locomotives, making it much easier to group equipment in to "eras" or "generations".
European model manufacturers have used a system of eras for a long time - Hattons thought they could bring it here without understanding the more complex history of our private industry rail system. Maybe they do that when discussing prototype history in Europe as well, I don't know.
Just like I don't know anything about modern diesels here, I don't really know much about European trains - real or model - old or current. You can't be an expert on everything.
Not really the same thing as the diesel discussion.
Maybe this idea will help make it more clear.
I remember rail historians, industry people, and modelers describing diesels as 1st generation and 2nd generation in the early 70's when that was all there was.
To me personally, I don't consider it as eras. I call it locomotive development and improvements. Steam had a constant development from it's inception and diesels are just another development and improvement. It's a continuation of trying to move products as inexpensive as possible. Each railroad developed locomotives as they saw fit. They used to be custom made for the job they were intended to do. Until the development of the diesel locomotive showed that they could customize the needed motive power for the job just by adding or subtracting units in a consist. It took one person to operate one or a consist of six or more.
To me there are 3 eras. Beginning infant stage of railroads before anything was standardized. Steam. And then diesel/electric. This also goes to generations. Generations of steam locomotive development was eventually replaced by generations of diesel locomotive development. The same would apply to electric locomotive development.
Just my thoughts on the subject.
Pete.
wrench567 To me personally, I don't consider it as eras. I call it locomotive development and improvements. Steam had a constant development from it's inception and diesels are just another development and improvement. It's a continuation of trying to move products as inexpensive as possible. Each railroad developed locomotives as they saw fit. They used to be custom made for the job they were intended to do. Until the development of the diesel locomotive showed that they could customize the needed motive power for the job just by adding or subtracting units in a consist. It took one person to operate one or a consist of six or more. To me there are 3 eras. Beginning infant stage of railroads before anything was standardized. Steam. And then diesel/electric. This also goes to generations. Generations of steam locomotive development was eventually replaced by generations of diesel locomotive development. The same would apply to electric locomotive development. Just my thoughts on the subject. Pete.
Agreed, it is about development, not time frame. I think the OP is trying to split too many hairs in that regard.
I always felt that first generation diesels were things like boxcab and the second generation as the ones that looked more like the ones that lasted into the 70's like the vo 660.
I think that some of the 'era' discussion has to do with appearance, rather than structure: while there's a world of difference between an SD45 and an SD45-2, most railfans aren't going to treat it as more than a spotting difference (e.g. the shock absorbers on the axleboxes).
First-generation and second-generation are 'canon' from sources like the DSG, with there being a couple of potential areas of division (for example, introduction of better turbocharging and detail-design improvements to go from 2400hp for a 'large' locomotive up to the 3600hp range). BUT you still see examples of B-B high-horsepower locomotives for fast freight service.
Third generation to me starts with adoption of higher-horsepower and C trucks, perhaps between the SD60 and SD70. It rapidly develops into the 'modern standard' of 4400hp with an S.520 or newer cab structure. The point is that locomotives in this era are still modern and in regular use, no few without a repaint since the early 1990s (Grinstein green executive scheme or Super Fleet warbonnet, anyone?) and current development tendency is to rebuild these "visually in-kind" rather than construct new Tier 4 or newer power.
AC is significant, especially for a railroad like NS that made such a point of retaining DC for so long, but I don't know if that 'alone' constitutes a distinctive gap between 'eras' for railfan purposes... you could make at least as good a case for the introduction of traction alternators in place of generators in the Sixties... and to me that doesn't qualify as an 'era' defining locomotive appearance and power. I am of the same opinion regarding progressively larger radiator capacity for various reasons.
That is also true of the evolution (pun not really intended) between the FDL and GEVO engines, or really between the 710 and 1010.
Very hard to tell the difference in outline when you have a couple of converted slug-mother 4400s and a FLXdrive; we didn't have an era for natural-gas conversions, and unless something unexpected changes with hydrogen fuel-cell locomotives there really isn't a visual era for those coming up. I don't see making an era for Iden's electric tender any more than we do for GE MATEs.
Where a major 'era' should (imho) have been drawn was with the advent of 6000hp locomotives from the major builders -- all of which dropped without trace in the United States, rebuilt to 4400 standard when they could be. These more or less presume AC inverter drive to be practical (justifying the contemporary added unit cost with the higher unit horsepower available...)
ATLANTIC CENTRAL Maybe this idea will help make it more clear. I remember rail historians, industry people, and modelers describing diesels as 1st generation and 2nd generation in the early 70's when that was all there was. Sheldon
A definition that I heard back then was that a first generation diesel was a diesel designed to replace a steam engine, and a second generation diesel was a diesel designed to replace a first generation diesel.
wjstix ATLANTIC CENTRAL Maybe this idea will help make it more clear. I remember rail historians, industry people, and modelers describing diesels as 1st generation and 2nd generation in the early 70's when that was all there was. Sheldon A definition that I heard back then was that a first generation diesel was a diesel designed to replace a steam engine, and a second generation diesel was a diesel designed to replace a first generation diesel.
Yes, that has been covered several times already in this thread. That has always s used been my understanding as well.
ATLANTIC CENTRALYes, that has been covered several times already in this thread. That has always s used been my understanding as well. Sheldon
I'd say that definition probably still makes the most sense today. Afterall, a GP20 is really nothing more than a turbocharged GP7, with slightly different horsepower variants in between.
- Douglas
ATLANTIC CENTRALAgreed, it is about development, not time frame. I think the OP is trying to split too many hairs in that regard.
Indeed. Over in the fighter jet world, they break up the jets into generations too. Not hobbyists, actual military planners. Instead of hair splitting, they just cram Generation 4.5 or Generation 4+ in there where they need to place something that doesn't fit neatly into the box. Don't need to over-divide.
I stumbled on this short text:
https://www.railway-technology.com/features/featuretracks-in-time-200-years-of-locomotive-technology-4517022/?cf-view
That I found quite interesting in this regard. The source appears to be European, but aims for a global perspective (CN is cited...). The author (Chris Lo) distinguishes the following:
snjroy wrench567 To me personally, I don't consider it as eras. I call it locomotive development and improvements. Steam had a constant development from it's inception and diesels are just another development and improvement. It's a continuation of trying to move products as inexpensive as possible. Each railroad developed locomotives as they saw fit. They used to be custom made for the job they were intended to do. Until the development of the diesel locomotive showed that they could customize the needed motive power for the job just by adding or subtracting units in a consist. It took one person to operate one or a consist of six or more. To me there are 3 eras. Beginning infant stage of railroads before anything was standardized. Steam. And then diesel/electric. This also goes to generations. Generations of steam locomotive development was eventually replaced by generations of diesel locomotive development. The same would apply to electric locomotive development. Just my thoughts on the subject. Pete. I'm more interested in the steam era, but I'll put my two-cents here and agree with Pete. I would think that technology would be the main driver when defining a "generation", and how popular that technology was in a rough period of time. I stumbled on this short text: https://www.railway-technology.com/features/featuretracks-in-time-200-years-of-locomotive-technology-4517022/?cf-view That I found quite interesting in this regard. The source appears to be European, but aims for a global perspective (CN is cited...). The author (Chris Lo) distinguishes the following: 1804: Trevithick kicks off the age of steam power 1812-1848: moving steam forward 1879: electrifying the railways 1892 – 1945: the dieselisation process 1945-present: the rise of diesel-electric 21st century trends: LNG and hydrail That last category is still in development – and probably up to debate… Simon
I'm more interested in the steam era, but I'll put my two-cents here and agree with Pete. I would think that technology would be the main driver when defining a "generation", and how popular that technology was in a rough period of time.
But that is about railroading in total. The article in question that the OP is referring to is just about diesel-electric locomotive history.
And term commonly used is "generation". And has always been understood to mean that 1st generation diesels are the ones that replaced steam locomotives.
And thereby "second generation" diesels are locos purchased to replace and/or upgrade that "first generation" of diesels.
The OP's question/comment does not seem to challenge that idea much but focuses more on exactly where that boundary is, and what constitutes the next boundry? 3rd generation? 4th generation, etc.
As a lifelong modeler and student of North American railroading, I find it very difficult to pigeon hole North American rail development into an "era" system of any type. However if you narrow the subject just to diesel motive power development, there is a clear distinction between those locos of the late 40's and the 50's that totally displaced steam, and the next "generation" that from the late 50''s thru the early 70's began the cycle of replacement and upgrading of that original fleet.
Diesels before 1940, or 1945, were the test bed, the development experiments, that allowed the EMD FT and F3, the ALCO RS series and FA series to replace steam. While important, those early locos would just be a footnote had they not been successful.
Steam moved America until after WWII, that was the true dawn of the diesel age in North American railroading.
And at the risk of being called an arrogant American, other peoples "global perspective" on railroad development and history does not apply much to this topic in my view. It is about North American diesels. The OP is complaining about a problem that does not exist. And a great number of modelers and railroad historians in North America have understood and used these definitions for five or six decades now, since they first observed the replacement of the "first generation".
In the simplest terms - F3's, F7's and GP7's replaced steam, and GP30's, GP18's and GP35's replaced F3's, F7's and GP7's. The waters do get a little muddy for the 3rd and 4th generation, and so on.
And again, as a modeler I am stuck in the middle of that first generation, happily ignoring what comes next. It is always September 1954 here.....
So if we want to take a sidebar into steam developement, the chart above has zero relevance to North American history.
The high water mark of steam in North America was clearly 1935 to 1945.
The Big Boy
The Allegheny
The Challenger
ALL the Lima super power designs: 4-8-2's, 4-10-2's, 2-6-6-6, etc
Virtually all the great 4-8-4's (half of which came from LIMA)
The final evolution of N&W excellence: J-1, Y-6b, Class A
The final refinement of the 4-8-2 by the B&O
The ultimate Mikados - DT&I 800's (a LIMA super power "baby" Berk), the B&O Q4d, GN 0-8
Electrifying the railways - 1879
Really? The first electrified mainline trackage in the US was the Baltimore Howard Street tunnel buit in 1891 and electricfied in 1895 and un-electrified in 1952 when good ventilation made the use of diesels practical.
For Class I railroading in North America the PRR NorthEast Corridor is the only "effective" electricfication that has ever been done, and today all the freight and a third of the passenger service on much of that trackage is diesel powered?
Only subways, trolleys, interurbans, and light rail systems have effectively used electrification outside the North East. Electrification requires dense traffic levels to be energy efficient. That leaves out most of North America by any measure.
My point, the scope of rail history, here in North America, or around the globe, cannot be boiled down to a six catagory chart......
Highly unlikey that Gen 7 diesels and trucks alike will be running on lithium batteries, but some Class 1 diesels do run on compressed natural gas (CNG) in the US conributing their to the "carbon footprint". In parts of Europe diesels now run on carbon free / green hydrogen fuel, and soon all combustion locomotive engines, jet planes, trucks , buses, and cars, starting here in the US within the near future, notwitstanding steel mills, power plants, refineries, Etc. alll using hydrogen fuel as an energy feed stock. I know this technology exist because I'm an industial real estate broker representing a Green Energy-Wall Street investment group seeking hydrogen development sites throughout the USA, in partiicular the California & NJ/NY markets, also the Chicargo area, Northern Indiana and Ohio. BT NJ
I believe we're in Generation 5. With the Gov't regulations of tier 2 emissions that began 2003, starting the GE Gevo ES44AC and EMD SD70ACe.
Amtrak America, 1971-Present.