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Articulated diesel?

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Articulated diesel?
Posted by Boyd on Wednesday, January 6, 2016 4:02 PM

Have any of the locomotive companies made an articulated diesel? Like a DD40x but bendy. Would it make maintainance any easier?

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Posted by M636C on Wednesday, January 6, 2016 4:26 PM

While not actually articulated, The New Zealand Railways 1000 HP DJ class, built by Hitachi (I think) had three two axle trucks with the centre one free to move laterally in curves.

A couple of these are preserved on the Taieri Gorge Railway, and the running through curves feels a bit odd with all the trucks moving a little.

The Trains tour in October will be going there.

Of course, with a truck where the fuel tank should be, you have to find somewhere else for the fuel.

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Posted by Semper Vaporo on Wednesday, January 6, 2016 4:29 PM

I think that is what we see on almost every train these days... two Dismals connected together, but they don't bother with a drawbar between them, just use normal couplers, makes maintenance so much easier to be able to replace the half in need of maintenance and keep the other half in service.

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Posted by erikem on Wednesday, January 6, 2016 5:41 PM

The Baldwin centipedes were articulated, but most diesels used individually pivoting trucks.

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Posted by mudchicken on Wednesday, January 6, 2016 6:25 PM

erikem

The Baldwin centipedes were articulated, but most diesels used individually pivoting trucks.

 

and you saw how popular those weren't, powerpacks and all on top of a custom wheelset more attuned to electrics or steam engines.

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Posted by MidlandMike on Wednesday, January 6, 2016 9:15 PM

GM's early road diesel, the FT, was often built in A-B sets connected with drawbars.

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Posted by ericsp on Wednesday, January 6, 2016 9:22 PM

More parts, espicially moving or "bendy" parts, mean more maintenance and repairs.

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Posted by BaltACD on Wednesday, January 6, 2016 9:23 PM

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.

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Posted by CShaveRR on Wednesday, January 6, 2016 9:24 PM

EMD's TR-model locomotves were, as far as I know, all drawbar-connected "cow-and-calf" locomotives.  It made more sense to replace the drawbars with ordinary couplers, but I know that one of CGW's TR2s had drawbars as recently as 1971, when I worked with it (others had been separated).

But there was rarely a need to produce a diesel in a long-enough carbody that had to be kept straight, as was necessary for a steam locomotive's firebox/boiler/smokebox assembly. 

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Posted by MidlandMike on Wednesday, January 6, 2016 9:51 PM

Boyd

Have any of the locomotive companies made an articulated diesel? Like a DD40x but bendy. Would it make maintainance any easier?

 

GE made the U50 for UP.  It had B+B-B+B wheel arrangement.  The span bolster trucks apparently came from earlier gas turbine engines.

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Posted by MidlandMike on Wednesday, January 6, 2016 10:05 PM

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.

 

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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Posted by Boyd on Wednesday, January 6, 2016 11:46 PM

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. 

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Posted by ORNHOO on Friday, January 8, 2016 12:41 AM
Wasn't the SF-1 (1st motive power for the Super Chief) described as an articulated? I'm not sure if that means permanently coupled, drawbar, or what.
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Posted by rcdrye on Friday, January 8, 2016 6:28 AM

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.

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Posted by tree68 on Friday, January 8, 2016 9:02 AM

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.

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.

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Posted by DS4-4-1000 on Friday, January 8, 2016 9:39 AM

Boyd
In 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.

 

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Posted by Euclid on Friday, January 8, 2016 10:09 AM
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:
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Posted by Euclid on Friday, January 8, 2016 10:19 AM
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:
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Posted by carnej1 on Friday, January 8, 2016 11:21 AM

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:
 

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..

 

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Posted by wjstix on Friday, January 8, 2016 11:36 AM

MidlandMike

GM's early road diesel, the FT, was often built in A-B sets connected with drawbars.

 
Yes, as designed and first produced, there was no provision for couplers between the A and B units, only a drawbar. There wasn't even a door you could close between the two units. A railroad could buy an A-B or A-A set with drawbars. ATSF wanted the flexibility of having couplers at both ends, and EMD was able to rig up a coupler to fit in the space for the drawbar.
 
Many railroads bought, numbered, and operated F units in A-B-B-A sets, often with drawbars between the A and B units. The units were thought of as parts of one engine, and the four unit set had roughly the same horsepower as a typical Mallet articulated steam engine of the time.
 
BTW many early diesels were serviced in steam-era roundhouses, and an A-B set of F's would fit on a typical turntable, but not an A-B-A or A-B-B set.
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Posted by rcdrye on Friday, January 8, 2016 1:21 PM

Alco's C855 and GE's U50 (also GE Gas-Turbines for UP) had AAR type B trucks on span bolsters.

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Posted by ORNHOO on Friday, January 8, 2016 6:19 PM
if 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.)
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Posted by tree68 on Friday, January 8, 2016 7:06 PM

ORNHOO
if 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...

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Posted by MidlandMike on Friday, January 8, 2016 9:27 PM

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.

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Posted by Deggesty on Friday, January 8, 2016 9:53 PM

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.

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Posted by DSchmitt on Saturday, January 9, 2016 12:49 AM

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.

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Posted by Boyd on Saturday, January 9, 2016 12:56 AM

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. 

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Posted by DSchmitt on Saturday, January 9, 2016 1:11 AM

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. 

 

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.

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Posted by CSSHEGEWISCH on Saturday, January 9, 2016 7:07 AM

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.

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Posted by rcdrye on Saturday, January 9, 2016 10:02 AM

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.

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