The concern is with placing the truck pivots at the appropriate balance points for weight distribution and still have them under the tender and able to pivot independently of each other. With much of the weight forward, the three-axle truck might have to be pushed forward to get its pivot under the rear 3/5 worth of mass, with the two-axle truck now having to be even further forward. Not that this is wrong; in fact there can be advantages to having the ‘lead’ tender truck far forward. I can think offhand of German, British, and Japanese prototypes that did so.
I don’t remember whether this is a water-bottom tender with solid cast under frame or made lightweight. That might affect placement of the reversed pivots.
The colossal overhang at the rear of some of the pedestal tender designs is a different example of the concern. Not all of it is to shorten the tender so everything fits on a shorter turntable…
I don’t know if a true balance study was made of the 64-ton “4-10-2” tender in the C1a proposal, but it would be interesting to see where that trailing axle wound up ‘optimized’ in position. I have read a number of different accounts of that ‘next step’ in pedestal-tender enlargement but I don’t recall seeing any dimensioned drawings.
Loads of comments there – my ‘original’ quotes are double, your replies to them are single. I’m using the old Internet quotation with just angle brackets at the start of the quote… let me go through and put quote tags in as I should have.
In a way that’s exactly what would happen at the front: the lead truck would have to have its center pin (or bolsterless center) far enough forward that the truck swing clears the three-axle truck in its new balance position. That may put the leading axle on the lead truck forward of the tender; in fact there is no objective reason the pivot point can’t be forward of the tender and the lead truck made to act like a Jacobs articulated truck steering the back end of something like a big 4-6-0.
GO FOR IT! I for one would like to see as many as you can develop.
See the Allegheny tender for an example ‘just shy’ of a 4’4’.
The C1a tender (with 64T and a water bottom) could in theory have eight-axle trucks, since most of the ‘overhang’ effect on turntables (or in balance) is changed by the ‘trailing’ truck. Exactly where the two trucks for that would go is TBA, but we could get reasonably close… fthe stoker trough gets progressively plated off as the huge coal pile empties, so the fuel weight will stay reasonably between the truck bearing points over a long range of drawdown…
There are suspension and guiding advantages to the Centipede; some of the rationale is described (in an early version) in the Locomotive Cyclopedias. Interestingly Kiefer noted at one point that the ‘lateral guiding’ touted for the original Fabreeka-shear-spring lateral suspension was not observed to the extent claimed. This was also the conclusion when the same approach was tried by
Lots and lots of lock and load… that ought to be a punk song. My crApple criPhone kept correcting ‘lots’ to ‘loads’ automatically just as I went to save the post; did it at least four times by actual count.
Meanwhile excuse unedited quoted lines at the end; I have to save every 5 minutes or so or the page will reload and delete my loads and loads of posting.
In the spirit of the base manager, back when the Air Corps was part of the cavalry, who became aware that trainees were making an alarming number of hard landings. His response was to post a standing order that henceforth no more hard landings were to be made… [:)]
Phone is what I have in the field; I’m seldom where I have wireless access on the laptops.
Hard landings and erroneous postings are apples and carrots.
Novices will make a lot of hard landings until they are no longer novices (and even then a hard landing is still possible). Posting when you know your ‘machine’ is not up to your normal standards - that is on you.
I could post from my phone - I choose not to - not until I have access to a desktop or laptop.
To get back to the subject of the thread, I’m surprised that nobody appears to have commented on this post. Despite the name of the organisation involved, this appears to be an HO scale model running on an English prototype oo scale model railway. It would not be surprising to find that the model was made in the UK.
