From a purely operational perspective any M.U'd multi-locomotive consist could be considered "articulated" as it is a modular tractive effort producing system intended to pull(or push if the units are DPU's/Helpers) a train of unpowered vehicles with flexible linkages between the power units..
About the only modern idea I can think of that might meet the exact definition is this:
https://patents.google.com/patent/US20110067390A1/en?q=mobile&q=diesel&q=power+system&q=separated&q=engine&q=exhaust&assignee=Clean+Rolling+Power%2c+LLC
The patent describes installing auxiliary cooling, exhaust after-treatment and waste heat recovery systems on a tender unit coupled to the locomotive and connected by flexible piping.
The industry doesn't seem to be showing any interest in the idea. Given the added complexity one can see why.......
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
I'll throw out the following proposal to see if we can get some sort of consensus. Since Wiener's definition of an articulated locomotive is overly broad when applied to diesels, an articulated diesel may be defined as either: A. an inseparable jointed arrangement such as ATSF M-190, or B. a jointed arrangement in which tractive or buff forces are transmitted through the truck frames only such as a Baldwin Centipede or the Baldwin experimentals like BLW 58501.
Note that this excludes multiple units linked by drawbars such as FT sets or cow-calf sets. Drawbars were often replaced by couplers in many of such sets.
Paul_D_North_Jr Euclid With a diesel locomotive, D-D trucks are likely to be too long to negotiate curves, so each truck must be articulated. . . . [snipped - PDN] The 1960's "2 locomotives on 1 frame" period in the US did have these 2 EMD models with D-D trucks: http://www.thedieselshop.us/Data%20EMD%20DD35A.HTML http://www.thedieselshop.us/Data%20EMD%20DDA40X.HTML "Centennial" - Paul North.
Euclid With a diesel locomotive, D-D trucks are likely to be too long to negotiate curves, so each truck must be articulated. . . . [snipped - PDN]
The 1960's "2 locomotives on 1 frame" period in the US did have these 2 EMD models with D-D trucks:
http://www.thedieselshop.us/Data%20EMD%20DD35A.HTML
http://www.thedieselshop.us/Data%20EMD%20DDA40X.HTML "Centennial"
- Paul North.
Don't forget that the Baldwin Centipedes had "D" trucks as did the Little Joe electrics and those two giant electrics that GN had.
It seems that the EMD TR1 [Cow&Calf] has not been mentioned as a type in this Thread.
ICRR had two pair, on Blomberg-style Trucks, used originally around Chicago and then St. Louis until retired.
UPRR had some that they referred to as 'Transfer Sets' (total 8(?) were used as helpers on Cajon Pass, and were specially equipped for that service-see note on linked 'Railpictures' photo- @ http://www.railpictures.net/viewphoto.php?id=516942&nseq=1
ALCO had also made Cow&Calf models for Oliver Mining Co in Minnesota (see note) @"... Baldwin VO-1000, DS-4-4-10, S-12 and S-8 cow/calf locomotives compromised a majority of the mine railroad power, followed by EMD SW-9, SW-1200 and TR-6 cow/calf models and in third place were Alco S-2, RS-2 and S-6 cow/calf models..."
from link @ http://www.missabe.com/cms/about-oliver
From a purely technical standpoint virtually every diesel bought by class 1 railroads ARE articulated engines already, the drivers are not rigidly attached to the frame of the locomotive and can rotate with respect to the frame.
Dave H. Painted side goes up. My website : wnbranch.com
EuclidWith a diesel locomotive, D-D trucks are likely to be too long to negotiate curves, so each truck must be articulated. . . . [snipped - PDN]
Euclid The AT&SF experimented with articulated steam locomotives where the two frames were rigidly attached to the boiler, but the boiler itself articulated by the hinge effect of a bellows connection in the boiler barrel. See Figure 4 here: http://www.catskillarchive.com/rrextra/blwmal00.Html
Your tractor example has its wheels fixed mounted, and turning is done at the pivot. This is like the AT&SF flexible boiler experiment, except that the flexible boiler was not really a pivot. It was a failed experiment, whereas the articulated locos with the articulation at the frames became the standard. The articulated frame carried thru to early heavy electrics, and even a few Baldwin diesels. The Balldwin centipede perhaps could have been fully (body) articulated since it had two diesel engines, and it had enough axels to support a split body. However, if you look at the DD40X, you will see the small footprint of the 4 axel trucks at each end. If you tried to balance each half of the articulated bodies over the (fixed mounted ?) truck, the ends of the loco would have large overhang that would work aginst smooth coupling force transfer.
Long Island RR's "Mike and Ike" were a pair of single truck, drawbar connected locomotives (later separated) that were intended to operate as a single locomotive.
I think that most of us could agree to go with Lionel Wiener's definitions of articulated, semi-articulated and other types of flexible locomotives. They don't apply very well to diesels but it gives us a starting point.
Boyd Articulated, as in a pivot in the middle with a hinge like an International 3388 4wd tractor my family had on our farm before it was sold in 1981. That was my intent when I started this thread.
Articulated, as in a pivot in the middle with a hinge like an International 3388 4wd tractor my family had on our farm before it was sold in 1981. That was my intent when I started this thread.
Using that as the criteria, none of the locomotives mentioned so far except the expermental ATSF loco referenced by Euclid in his post and perhaps Garretts are articulated.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Modeling the "Fargo Area Rapid Transit" in O scale 3 rail.
Articulated locomotive usually means a steam locomotive with one or more engine units which can move independent of the main frame.
Besides the types we usually think of (Mallet, Garrett, Meyer) Heislers, Shays and Climaxes and some others can also be considerated articulated.
Actually in a broad sense any diesel locomotive with two or more trucks could be considered "articulated". They consist of a power generator on one frame (analogous to a steam locomotive boiler) and units on separate frames that can move independent of the main frame (the trucks with traction motors) to convert the power to movement on the rails.
Since a slug can stand alone when disconnected from its source of power, I do not think that you can consider one as part of an articulated locomotive.
Do calves have separate controls? I imagine that they do so they, just as B units, can be moved about even though they do not have cabs.
Beyer-Garratts are articulated: if you remove one engine, you have to prop the part that had rested on it up, just as is necessary with any articulated locomotive that is/was a familiar sight in this country.
Johnny
Speaking of something that can't work without the other, what about slugs? I don't guess anyone thinks of them as articulated, but they are a flexable arrangement.
ORNHOOif the definition is one part cannot work without the other you might include the natural gas diesels with their CNG tenders, but then EVERY steam locomotive was articulated (except tanks, fireless, etc.)
Which is why I excluded steam locos, although the Garratt was, indeed, articulated.
Even though a steamer needs its tender (unless it's a tank engine), both the locomotive and the tender can be moved independently. If the tender was actually supported by the locomotive (ie, no front trucks on the tender), it would be a different story.
Kinda like another thing I won't mention - I can't define it, but I know it when I see it...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Alco's C855 and GE's U50 (also GE Gas-Turbines for UP) had AAR type B trucks on span bolsters.
MidlandMike GM's early road diesel, the FT, was often built in A-B sets connected with drawbars.
GM's early road diesel, the FT, was often built in A-B sets connected with drawbars.
Euclid With a diesel locomotive, D-D trucks are likely to be too long to negotiate curves, so each truck must be articulated. One way is to use two B-B trucks with a span bolster, and then connect the center of the span bolster to the center bearing of the locomotive frame. This is common on Brazilian locomotives such as shown here: http://www.thedieselshop.us/BrazilLocos.HTML
True , but note that one of the major Brazillian operators of Bolster connected BBBB trucked units also rosters SD45 variants with DD trucks so both designs work for them..
BoydIn the 70s as a child I thought that they could make a diesel/pneumatic locomotive.
That was already done in the 1920s. in "Dawn of the Diesel Age" Kirkland shows photos of some of the alternate transmissions tried. Pneumatic, direct gearbox (3 speed no less! keep your foot off of the clutch), siderods from the crankshaft and probably one or two I am forgetting.
BaltACD To me - drawbar connected and articulated are totally different animals. Articulated is two carbodies sharing a common truck at their coupling - the original Zephyrs were articulated.
To me - drawbar connected and articulated are totally different animals. Articulated is two carbodies sharing a common truck at their coupling - the original Zephyrs were articulated.
I was going to say that I'd take that a step further and say that articulated means two parts that must be flexible but cannot be separated without making both useless. That would include consists where a truck is shared between two cars.
But that would include today's intermodal "cars," which do just that. I can't say that I've heard them called articulated.
I must exclude from that steam locomotives and tenders, and B units.
I think most folks think of articulated as a something that could be one, but is made into two for sake of flexibility.
Some of UP's M1000x sets had drawbars between units. AT&SF 1 and 1A (original EMC Super Chief power) had couplers on both ends.
This could be a future Trains article: early, oddball and articulated diesel locomotives. In the 70s as a child I thought that they could make a diesel/pneumatic locomotive. I was thinking of a lot of things as a child in the 70s: opposed piston engine,,, as in two Pistons per cylinder facing each other with two crankshafts linked via gears. My engineer brother looked it up and it turned out to be a Fairbanks Morse.
Articulation just means a flexible joint. Car bodies sharing a common truck is one type of articulation. Some steam engines and early electrics, as well as the Centipededs, had articulated frames.
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