City of Truro information request

[spencerman]

In my inimitable fashion I always seem to start planning the next project before I have the current ones finished, but since one of them is progressing well, I thought that the research should be started for the next. This is one that some say should be avoided, but after all it does not involve the potential of killing an expensive brass kit! So I shall have a go.
The first question is does anyone have the information where I can get a good drawing of Truro in superheated form, or have a drawing and can answer the relevant questions. I have the Dapol kit and the Branchlines detailing and chassis packs. Branchlines say that the smokebox is 3mm too short compared to the prototype (9 real inches I guess!). I have no suitable side on pictures to check this - it is thought that the missing 3mm/9" is in front of the centre line of the chimney. It just so happens that on checking my kit I found that the firebox end of the boiler moulding was malformed (melted blob..) - any way the kind lady at Dapol sent me a new kit. So I am now ideally set up for a little cut and shut - after the cut and shut exercises involved in the Deltic prototype (refer Ivan Tan's detailed treatise) - I am willing to try it! (I shall post the DP1 saga in due course.) Also the uprise in the running plate is in the wrong place - in for a penny as they say. A good side drawing should nail that too.
Also there is no mention of P4 construction for the chassis, but I guess that P4 spacers are the answer as is normal, just be prepared for more than a little surgery on the Dapol superstructure and running plate as I was advised by Brian. Any experience of this procedure please???

Best regards to all and thanks in advance for any help and info.

Philip

[davidb]

Jim Russell's book on GW engines, Vol 2, p15 has the attached diagram.

David

City of Truro_r.jpg (135.7 KiB) Viewed 1296 times

[spencerman]

Thanks very much David. I think that proves the theory. I do not have that book. Great info.....

Further though has anyone tried this?

Is it that groundbreaking in P4?

I saw Truro many many times when I was a kid up on the embankment opposit 81A - Old Oak Common Lane was a short bike ride
from home and safe in those days - bless the hole in the chain link fence so you could scramble up the bank....

[nigelcliffe]

I trust you are aware that Bachmann have said they will be producing a new model of the 3700 class in the not too distant future.

Just mentioning it to avoid a "bugger sods law" if you were to spend months improving the old Airfix kit, making a mechanism, and only to find a RTR loco which may prove to be a better starting point.

- Nigel

[BryanJohnson]

Painted and lined examples of the City are in the Bachmann display stand at the York show this weekend, so it not be too far off release.

[spencerman]

Ooh err so maybe wait a bit.
Just checked out the Bachmann website - imminent is the word I guess.

Thanks Nigel and Bryan.

Back to the planning board then.

[grovenor-2685]

Further though has anyone tried this? Is it that groundbreaking in P4?

Try Model Railways Vol 5 No 12, December 1976, "Motorising the Airfix City of Truro" by Darrell Ward, pages 600 - 604.
I think the ground was broken then.
Today we would use a different motor and gears but otherwise a comprehensive article with a number of good ideas in it.

MR12-76.jpg (74.95 KiB) Viewed 1180 times

Regards
Keith

[Re6/6]

Out now if anyone interested http://www.ehattons.com/stocklist/resul ... f%20london and available in my local model shop.

[grovenor-2685]

Looking at the £104 for the new model, back in 1976 Darrell calculated his cost less paint as less than four pounds, being the kit at 4/6 plus motor, gears and nameplates. The rest he made himself from materials in stock.
Keith

[Horsetan]

......after the cut and shut exercises involved in the Deltic prototype (refer Ivan Tan's detailed treatise) ....

I see my malign influence on finescale modelling has spread

Jim Russell's book on GW engines, Vol 2, p15 has the attached diagram.

That diagram has an error in the footplate valance, where it curves up. This is about 3mm too far forward. The error was duly repeated in the Kitmaster/Airfix/Dapol kit! But my question is: which error came first? The drawing or the kit?

[spencerman]

Good spot Ivan. Only a photo will nail that one then.
Perhaps i will persevere here - as long as P4 is doable.
By the way thanks all for the links - certainly the photos of the Bachmann model would confirm that
the missing smokebox scale 3mm is in front of the chimney, so
it appears to me.
Now where do I get that article from? A few phone calls later I think.

Thanks everyone for all the invaluable help.
Philip

[Horsetan]

Note also that the Branchlines chassis fret has generic EM/P4 spacers. But I think it is possible to install the CSB suspension system in it.

Good spot Ivan. Only a photo will nail that one then.....

Ah, but the earlier drawing in the same Russell book, page 13 or 14, showing the saturated/non-superheated boiler with shorter smokebox (which latter the Kitmaster / Airfix / Dapol kit replicates), does have the correct footplate!

Branchlines say that the smokebox can be given the 3mm extension by taking a slice out of a second kit, but it seems a shame to waste a tenner just for that one section. Is there not a suitable plastic tube of that diameter which could be used instead?

[Wizard of the Moor]

Or a compass cutter and three discs of 40thou plastic sheet?

[spencerman]

Ivan and James

When I checked my original Dapol kit it turned out that the firebox was malformed - short blob type of thing,
and then the very nice lady at Dapol said no worries I shall send you a new kit - so the cut and shut has to
be done the easy and cost free way...Lusk of the demonic modeller i would say Ivan!

regards
Philip

[Horsetan]

....When I checked my original Dapol kit it turned out that the firebox was malformed - short blob type of thing,
and then the very nice lady at Dapol said no worries I shall send you a new kit - so the cut and shut has to
be done the easy and cost free way.....

Keep the boiler barrel from the faulty kit. That will give you a spare standard no.4 to use on something else, like a proper 61xx, or a 43xx, or even (I think) a 42/52/72xx.....

[Ealing]

Does anyone know how accurate the new Bachmann is? I'd worry as to how much work the Kitmaster/Dapol would need to bring it up to spec.

[Philip Hall]

Does anyone know how accurate the new Bachmann is?

I'd be interested in opinions on this as I've recently been asked about the amount of work needed to P4 one - indeed, if it's really worth doing. I think the main problem is with the depth of the hanging plate at the front end - it looks too shallow to me. Also, presumably to get the loco around train set curves, Bachmann have cut the top off the bogie frame above the springs, which looks very odd as the frame should really extend up behind the hanging plate. Given the extra width over our wheelsets we're going to have even more problems with that!

Obviously it ought to be possible, but some surgery is going to be needed if it's going to look right.

Philip

[Horsetan]

....Bachmann have cut the top off the bogie frame above the springs, which looks very odd as the frame should really extend up behind the hanging plate. Given the extra width over our wheelsets we're going to have even more problems with that!....

Paper or 5thou plasticard tops?

[HowardGWR]

....When I checked my original Dapol kit it turned out that the firebox was malformed - short blob type of thing,
and then the very nice lady at Dapol said no worries I shall send you a new kit - so the cut and shut has to
be done the easy and cost free way.....

Keep the boiler barrel from the faulty kit. That will give you a spare standard no.4 to use on something else, like a proper 61xx, or a 43xx, or even (I think) a 42/52/72xx.....

The 61xx uses a standard no 2 boiler but the 3150 banking class uses the number 4. The other examples given are correct. The No 4 was also tried out on a 2221 class 'County Tank' but was too heavy apparently (2230). Conversely a no 2 was tried out on a 38xx , but that didn't last either (3805). That reminds me that the 38xx used a No 4 of course, as, eventually the Aberdares from 2661 onwards and others retro-fitted. One could fill a book on boiler changes on the Dean type outside frame engines and the RCTS has done exactly that - so enough already.

Depending on chosen era, regardless of diameter, there were varying lengths of smokebox fitted. As always the RCTS books tell all, but in among the masses of 'Green With Rivets' examples, it would be interesting if modellers could try a few variations. I am wondering when someone will model the WSR 9351 'might have been' (well, actually 'became').

[doggeface]

[/b ]My OS Nock gives a standard size 4 boiler as having a smokebox length of 4'81/2" or 21.5mm in 4mm scale. This is confirmed in CJ Freezer's outline drawings for a taper boilered City. In both cases the funnel/chimney is 1mm (scale) to the aft of centre.

Peter [/b]

[grovenor-2685]

length of 4'81/2" or 21.5mm in 4mm scale.

Is that an Irish smokebox then? or have we had the track guage for P4 wrong all these years?
Regards
Keith

[doggeface]

Yes it must be! The real figures are as stated on one of two drawings! However, both drawings are confirmed as 4mm scale and the length (mm) is taken from them. This is not the first time by a long chalk that stated and measured have not married up!

[HowardGWR]

The City standard No 4 boiler has a diameter of 4ft 10 3/4 at its narrow end. The standard type 2 has a diameter of 4ft 5 1/8 at its narrow end. Both from RCTS Part 9.

Curiously (not noticed previously) figures are given in that part for the 'casing' . Standard No 2 is 7ft x 5ft 3", Standard No 4 is shewn as 7ft x 5ft 9".

I don't know to what this refers but, I think they mean the firebox length and diameter of joining tube plate at the wider end, respectively.

So the smokebox diameter is at least 5 ins different between No 2 and no 4. I would have thought cladding around the boiler would add an inch or two to the boiler diameter so that the smokebox may need to be greater so that it dovetails with the narrow end of the tapered boiler, but perhaps there are views about this?

I found this to be of relevance when scratchbuilding boiler barrels and smokeboxes. Guy Williams of Pendon fame, does not give much guidance on this aspect, IIRC.