The LNWR made some rigid framed 2-2-2-0s :-)
Greg.P.
The LNWR made some rigid framed 2-2-2-0s :-)
Greg.P.
: > : > : > "John Turner" wrote in message : > : > : > news: snipped-for-privacy@supernews.com... : > : > : >> The latest Princess Coronations appear to have the fixed : > : > rear bogie. : > : > : >>
: > : > : >> John. : > : > : > Pedantry and semantics demand that I tell you that 'two : > : > wheels do not a : > : > : > bogie make' - this two wheeled trailing supporter of many : > a : > : > firebox is : > : > : > called a 'pony truck'. We may have to come up with a : > revised : > : > name now : > : > : > that : > : > : > it doesn't actually swivel. Suggestions? : > : > : : > : > : It's a "fixed carrying axle". : > : > : : > : >
: > : > Surely that would make the loco a "4-6-2-0", think about : > it... : > : >
: > : : > : No. : >
: > Yes, as the loco in question needs a trailing truck of some : > description and not just a fixed axle (thus is would be missing : > it and would behave like a poorly designed 4-8-0), you obviously : > don't understand what a trailing truck does, it's not just a : > weight carrying axle - take away the suggestion of the axle being : > *fixed* and you are half way to a suitable name... : >
: : Compared to European 4-6-2s, British 4-6-2s did act like poorly : designed 4-8-0s (without the rear axle being powered) because : the trailing axle was not equalized and would therefore take : more than it's share of weight available for traction in situations : such as on the vertical curve into a gradient.
Gradients have f*ck all to do with it....
: : If a x-x-2 loco has the trailing axleboxes mounted on the rigid : mainframe(sprung obviously) then the axle is _not_ on a truck. : I could be wrong, but I understand the term for that is a rigid : or fixed axle.
....that is not what a trailing truck does (nor do they just carry locomotive weight), if that is all that was required there would be on need of a trailing truck!
: : If the Gresly etc trailing axles were allowed free sideplay, then : they were simple carrying axles with no other function. :
Whhhooooossssshhhhhh..........
You sure are clueless. :~(
What about Rowland Emett's 0-2-0?
And Adams?
"simon" wrote
Shouldn't the notation for that be a 4-8+8-4?
John.
"Jerry" wrote
It has certainly been referred to in learned circles as both a 4-6-4 AND a
4-6-2-2, and I think both are acceptable.
Is that so? I've not found any reference to that, although I believe that the P1 2-8-2s were so fitted for a while.
Since my original posting I've found the following which also suggests the acceptability of the 4-6-2-2 formation, although Gresley himself referred to the loco as a 'Hudson' (4-6-4) although the UK term for a loco with that wheel arrangement was generally 'Baltic'.
No. Because they are not fully independent power units. The rear unit on a Mallet is rigid, with the front unit hinged off it. Sometimes described as semi-articulated
When Whyte developed his notation in 1900 wheel arrangements were't as complicated as they later became.
Wikipedia has a web page but it is from an American perspective, especially the nicknames given to the various arrangements.
I'm sure I read it some place, perhaps it was nothing but a proposal, unfortunately one of my best references for the LNER CMEs is so written that such references are often single references to things that happened at a certain point in time and not what happened to certain class of loco during their lives IYSWIM - of course I might just have it all wrong (wouldn't be the first time I hear some shout...), as you say the P1s were fitted with boosters and so were some of the Atlantics.
Yeah, LNER Ivatt C1 No. 1419 had one fitted by Gresley between July
1923 and November 1935. Details in RCTS Locomotives of the LNER Part 3A, pages 26 to 29. See alsoGresley also rebuilt a couple of Raven's C7 (NER Z) Atlantics with boosters and reclassified them as C9, which was even stranger than the W1 classification as the booster was actually a bogie shared between the locomotive and tender so technically it was articulated and could arguably be termed a 4-4-4-4T [1]. More info in RCTS Part Locomotives of the LNER Part 3A pages 122-129,
While the C9 booster eventually worked well with a regular crew, the main problems with boosting the Atlantics were that the introduction of 'common user' rostering meant they would often be driven by crews with no experience of the booster and in the end the widespread introduction of A3s and A4s meant they were cascaded down to lesser duties and didn't need the extra power.
Notes:-
How would locomotives with Sturrock's steam tenbers be classified?
Or the first River Mite on the Ravenglass and Eskdale which was a monstrosity converted from two pacifics.
You appear to have a unwarrented negative turn of phrase. Imagine your (0-6-2) loco on a vertical curve between level and a steady upward gradient:
- The leading driving axle and the trailing carrying axle on an unsprung loco would be on the rails while the two inner axles would be clear of the rails. ie, those two axles would be carrying the weight normally carried by four.
- add springing: the two outer axles would compress their springs. The two inner axles would extend their springs which would mean they actually carried very little weight - the outer axles carry the majority.
- add equalization: The load is now carried equally by all four axles. The Gresleys didn't have equalization on the rear carrying axle - loop back to the second scenario where the weight is carried mainly on the outer axles - one of which is a carrying axle. Conclusion: Gradients (or more specifically changes in gradient) have everything to do with it.
Carrying axles generally have to purposes:
- carrying weight.
- guiding the loco. That second use is obviously secondary as not all locos have them.
Again, you demonstrate a negativeness without purpose.
Regards, Greg.P. NZ
That depends on whose notation you are using! " + " is normally used to indicate two seperate locomotive units permanently coupled together. examples might be the Swiss Ae 8/14 where two single cab 7 axle (4 driving axle) are coupled together. One might call an 0-6-0 with a Stirling driven tender an 0-6+6-0. (or 0-6-0+0-6-0) In most of Europe trucks and bogies are designated with a ' to show a separate frame: eg
- 4'2 0 for a leading bogie.
- 4 2 0 for a Crampton with the carrying wheels on the main frame.
I wasn't aware of that one even tough I am aware of Emett. It might well have had some stability problems?
There was me thinking those French Le Trague (sp?) 0-3-0s were the minimum.
Greg.P.
Here we go again, the Whyte system of wheel classification is just a system of classification. Originally described for UK steam engines of common occurence. Which presumably didnt include the one-offs, esoteric or articulated locos. Its academic, if require to extend to something differnt you would need to get some worthy body to do it. So some people describe an LMS Garrat as 2-6-0+0-6-2T whereas Tuplin says 2-6-6-2. Must say prefer the first to the second as conveys more info. Do continue to have fun debating but dont take it seriously :-)
Cheers, Simon
I've got a model of a NSWGR AD60 4-8-2+2-8-4 Garratt. Would Tuplin call that a 4-8-2-2-8-4?
Dunno, he mentions variety of Mallets :- 0-6-6-0, 2-10-10-2, 2-8-8-4,
4-8-8-4. Then a 'triplex' 2-8-8-8-2 in the form of Mallet 2-8-8-0 followed by a tender supported by a third set of 8 coupled wheels.But dont know if any of that answers your question.
Cheers, Simon
Not really. But don't worry about it. Merry Christmas.
"MartinS" wrote
Quaint beast which used the nearest coach as a zimmer-frame.
John.
Light-engine moves could have been interesting.
The " + " indicates two separate locos controlled as one. Admittedly you can disconnect the two loco units of a Garratt, but quite a bit will tend to drag on the rails afterwards!
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