LMS "Twin Bolster" Wagon Pair

[Richard08]

While poking around the MMP site looking for bits and bobs I came across this kit at an extremely affordable price. I know nothing about the prototype bar that some (as in the diagram this kit is for) were permanently coupled in pairs. Sounds a bit different, ergo I just had to have one, or is that a pair? While the BG is awaiting arrival of parts, ditto the festival scene and studiously avoiding gluing the roof on the QM brake van (fiddly + glue = lack of of enthusiasm) I decided to have a look in the box. The Radio Times wrapping the kit indicates it was made in 1995 (Blackadder was on the telly) but with the box never having been opened all the castings are 'perfect', I still get a buzz from well cast white metal. A brief scan through instructions and parts confirms this is a permanently coupled pair, but the instructions also cover the 'not permanently coupled' variety together with a coupe of other variations, so RTFM is a definite on this. Probably taking notes. I was, for no specific reason, expecting the wagons to be very short wheelbase jobbies, but it turns out they are 9ft 6in so somewhat larger than I expected. Apparently they were created in 1942 by cutting down 7-plank minerals. I've no idea if they made it to BR ownership (presumably) or how long they lasted, so a lot of searching for prototype info is going to be done - for the first time Paul Bartlett's excellent wagon site has failed me! Anyhow, here's the box and contents.

There's a small amount of cleaning up to do, but just look at the detail there - nuts that actually look like nuts

[Richard08]

Having cleaned up the castings and done trial assembly of the two wagons, wheels are needed before progressing, going to be a few days I fear (budgets and all that). In the meantime I've had zero luck with finding any photos, let alone in BR days, but I have found (boy have I looked at a lot of weird and wonderful wagons) the BR diagram for them - or at least something very close. The original diagram (LMS) was 2077, so not in the list on the drawing, but this drawing shows the bolsters not centred on the wagons but moved 'inwards' a bit, which matches the kit and is somewhat unique in that respect. The Diagram book was current in 1982, so I'm going to cheerfully assume that these did survive well into BR. The slight snag is that the drawing shows vacuum brakes which the kit doesn't have, so out with Modellers Licence No. 877654/12/DG444 and they are going to be grey. All that just to see if 3-hole wheels are ok. Insanity really. Here's the pretty picture:

It might be of interest to note the middle table, 'Excess Length', which is pretty much the same as the yellow 'absence of information' panel all wagons (in theory) carried. This was for use where TOPS was not available and allowed the Guard to calculate the weight, brake force and length of the train manually for the Driver's Slip. H M L E is the load state, Heavy, Medium, Light or Empty. If the loaders had not left a note (in the 'load clip') stating what the load state was it was assumed, unless it was clearly not the case, to be Heavy. Obviously an empty flat wagon can be seen to be empty, not so a van. This one doesn't have a line for excess length as a 10ft wheelbase wagon is 1 SLU (Standard Length Unit), or 21ft if you prefer. PGAs for example are 1.3 SLUs. The length is important as each route has a maximum permissible length (in SLUs) which could not be exceeded without a lot of kerfuffle. The limits on a train were a combination of: weight (including engine), brake force (including engine) and length (excluding engine), none of which could be over, under, over (pro rata) without the aforementioned kerfuffle. It was possible to proceed at reduced speed if brake force was lacking, but this was only in exceptional circumstances. Since I gave up the drink and can no longer be the boring bod in the corner of the saloon bar, I do it on the web instead They do things in metres these days I believe.

[Bigmet]

Interesting. This is covered in Peter Tatlows 'LNER wagons 4B' in terms of origins from early in WWII. These were conversions of pairs of 9' wb 12T/13T wooden bodied minerals (and in the case of the LNER examples photographed, all wooden framed with spoked wheels). The bolsters were moved off centre quite early, and the load reduced to 9T per wagon, permanently coupled with a drawbar, no buffers or drawgear on the inside ends. LNER wagon code was 'Twin Case'.

Presumably these proved so useful that the design was perpetuated post war. I would think the TOPS item is converted from 10' wb steel underframe VB fitted opens which were quickly becoming redundant from the late 50s on?

[Richard08]

Interesting. This is covered in Peter Tatlows 'LNER wagons 4B' in terms of origins from early in WWII. These were conversions of pairs of 9' wb 12T/13T wooden bodied minerals (and in the case of the LNER examples photographed, all wooden framed with spoked wheels). The bolsters were moved off centre quite early, and the load reduced to 9T per wagon, permanently coupled with a drawbar, no buffers or drawgear on the inside ends. LNER wagon code was 'Twin Case'.

Presumably these proved so useful that the design was perpetuated post war. I would think the TOPS item is converted from 10' wb steel underframe VB fitted opens which were quickly becoming redundant from the late 50s on?

Paraphrasing the notes in the instructions : The ones described above were the 'first batch' from 1942, initially just with ends cut off (I found a picture one of those, incredibly rickety looking), presumably done in something of a hurry - not even being re-painted completely aparently. The later ones were 'done properly' (still wartime) using steel chassied ex-minerals, some permanently coupled (LMS "Twins" with offset bolsters), some not (LNER "Twin Case" and LMS "Flat Case", both of which kept the bolster in the middle). They retained the door bangers for some reason.

The vast majority of this type of wagon in BR use were built in 1952 by BR (virtually all the photos on Paul Bartletts site are of these), but many were re-built into Plates at some point going by Mr. Bartlett's photo notes. Some of these later wartime conversions seem to have been converted to crane match trucks (two photos on the Bartlett site). The wheelbase on the kit is 9ft 6in which is a bit unusual, assuming this is right (I somehow doubt ABS would get this wrong), perhaps why they were chosen for conversion being non-standard? All the diagrams in the Diagram books are 10ft wheelbase which throws a spanner in the works.
In the absence of any exact details of what became of the pairs I'm applying the aforementioned modellers licence, I rather suspect they were converted to other uses when BR produced their own, but that's just going by lack of photos (yes, absence of evidence does not mean evidence of absence).
Here's that first batch photo - complete with BR number!

[Bigmet]

...In the absence of any exact details of what became of the pairs I'm applying the aforementioned modellers licence, I rather suspect they were converted to other uses when BR produced their own...

I'd suspect that the wooden framed 'wartime expedient' conversions were stripped of wheelsets, axleboxes and buffers, and converted to bonfires in fairly short order post war.

[Mountain]

The basic concept is that they work in pairs so a long load can be carried inbetween them. If the load is even longer, the wagons can be split as they get actively act as bodies and the load acts as the central structure of the "Vehicle".

I do not know if they separated them like this in standard gauge form, but in narrow gauge it was quite popular, especially when carrying long tree trunks and things like that. The only "Mistake" I made when scratchbuilding a pair of these was that I didn't realize that the load carrying crossbeams (If that is the word to use) was hinged in the centre. Obvious if one thinks about it but not apparent to me when I built a pain to my own design. (I could at a later date modify them but may require a complete rebuild where it maybe easier to make an additional pair and convert the original scratchbuilds into something else)).