Hornby Castle to P4?

[Steve Carter]

We welcomed a new Society member to SLAG and last Monday and he brought along a Hornby Castle that he is looking to convert to P4.

Even those of us with a “Southern” bias had to admit that it looks very nice.

Various suggestions were made as to wheels, spacers, etc to convert the loco. I explained all about the S4 Forum and encouraged our new member to sign up.

Until he gets around to doing so I thought I’ll try and help him by asking the question on his behalf!

So, has anyone converted a Hornby Castle to P4 please?

Any suggestions, tips, comments will be much appreciated.

I will try and persuade him to post his experiences.

Many thanks

Steve

[MarkS]

Yup, Tom Kidd in Brantford (here in Southern Ontario) converted one decades ago. Straight swap of wheels/axles and added spacers. Worked fine, I suspect there was some wear in the bearings.

[grovenor-2685]

decades ago

Might that perhaps have been Hornby Dublo
like this

Precision3.png

rather than the current Hornby?
I don't think the latter has yet been available for decades.
Regards
Keith

[craig_whilding]

The new Castle has only been on the shelf for less than two years so far..

Its on the Brassmasters list for an Easychas but I believe the GWR entries have now been relegated behind LMS locos due to the existing work the group has on the latter.

I decided against converting one of these due to the narrow 00 firebox and i'll stick with my Mitchell to build. It is a nicely painted model though.

I'd speak to Chris Gibbon about the tender, one of his chassis might be useable and could reduce drag.

[MarkS]

Oh, THAT Hornby... the fond memory of ozone and P4, the Castle pounding along the main line with 10 on...
I didn't realize 'new Hornby' did a new Castle, but then GWR isn't my thing...

[Tim V]

The new Hornby chassis, to my knowledge are pretty much all the same, so suggest your new member has a look at the Philip Hall articles on the Grange and M7 conversions.

[Philip Hall]

Thanks for the plug Tim. I will have a Castle to do sometime but it has not come to me yet. I suspect it will be of the same basic design, so should not present too many problems. I do recall seeing a sample model and I thought the front frames appeared quite set back, as you would expect with a 00 model, which means the valve rockers look a bit odd. But things like that come within the realms of whether you want to do anything about it or leave alone.

Philip

[Steve Carter]

Just to say thanks for all the suggestions/advice.

Steve

[Captain Kernow]

I decided against converting one of these due to the narrow 00 firebox and i'll stick with my Mitchell to build. It is a nicely painted model though

Are you saying that the (new) Hornby Castle firebox is too narrow, Craig?

[grovenor-2685]

Are you saying that the (new) Hornby Castle firebox is too narrow, Craig?

Well it would have to be to fit between the 00 back to back wouldn't it?

The comparison pictures of the Hornby and Bachmann standard 4s were interesting in showing different approaches to this problem.
Keith

[craig_whilding]

Are you saying that the (new) Hornby Castle firebox is too narrow, Craig?

Well it would have to be to fit between the 00 back to back wouldn't it?
The comparison pictures of the Hornby and Bachmann standard 4s were interesting in showing different approaches to this problem.
Keith

As Keith says, it has to be if you model it in full. Bachmann chop off the firebox under the footplate and recess the wheels into it, Hornby make the whole thing narrow so it looks complete.

[Bulwell Hall]

I have 'Beverston Castle' on the to-do shelf but as yet have done little with it. But when looking at it It does'nt strike me as being too narrow in the firebox but I have'nt checked it. Now the more recent 28xx is a different matter - the firebox is definitly a little "heavy round the waist"! I can live with it though as the alternative of building an etched kit does'nt bear thinking about - there's not enough years left!

I am sure that Philip Hall said he was going to post some photos of his recently converted Hornby 38xx or was I mistaken? I for one would be interested to see them.

Gerry

[Philip Hall]

Gerry,

Yes, I will sort out a picture or two but the first 38XX isn't completed yet although nearly finished. Just the cylinders, slidebars and crossheads left to do, along with slimming down all the coupling rod bosses. There are 38XXs in the pipeline as well, but the basic model is the same. It does seem that the width of the firebox, even on a P4 conversion, is slightly wider than the frames but then it would be just a bit, wouldn't it? Probably in 00 it looks worse, but I hadn't actually noticed there was something amiss until you mentioned it! As with you, it falls into the 'livable with' category. I should have the chance to look at a Castle at the end of the week.

And yes, you're right, there isn't enough time to build a Mitchell or a Finney for every loco!

Philip

[HowardGWR]

I've done a bit of measuring and I don't see any inaccuracy in the depiction of a number 1 boiler firebox on a Hornby 29xx body that I acquired. The firebox is not modelled below the footplate or splashers and the splashers are at full width. In fact the footplate width overall is a bit wide at 35mm (33.5 on the numerous diagrams I compared with in my pile of tomes). There are plenty of slight inaccuracies that arise during printing in these volumes, so do beware and read the measurements given, as they will be correct. In any case anyone wanting to model the firebox below the frames is wasting effort as nobody could see the lower firebox as it's hidden by the frames, except the front bit.

The Castle number 8 boiler is no different at the place we are talking about.

It's where the splashers are, that matters, is it not?

I've clearly missed a point here so put me right someone.

[grovenor-2685]

What you see on the model, above the footplate is not, of course, the firebox but the cladding, which may well be wider than the frames, in fact almost certainly will be as the actual firebox is normally a close fit between the frames to get the widest possible grate. On the GW locos with a footplate pretty much at frame top level the lower part of the firebox is pretty much invisible as Howard says. On the BR standards with the high running plate its a different matter hence the trouble both Hornby and Bachmann had with the Standard4.
Keith

[Philip Hall]

I've just measured a Hornby 38xx body at the bottom of the firebox where it meets the footplate, which is the dimension Gerry thinks has been increased a bit, and he's right, because it comes out at 19.1 mm (over the cladding of course). Looking at Russell's book and comparison with the parts from a Martin Finney kit it seems that this dimension should be 17.7mm or thereabouts. This would make sense because the firebox has to fit between the frames. I shall measure the Castle (hopefully I shall have one later in the week) and report back here.

Either way, I think it's not really that bad, not too obvious, very difficult to put right and therefore I shan't bother. It will be more of a challenge trying to make the visible gearbox less obvious where it juts out in front of the firebox. Here the 38XX with its fire iron tunnel on one side and the reversing rod on the other is the best bet. Mine will be a 28xx (thanks to Howard pointing out a cheap deal from Hattons on here a while back) so I'll have to only run the engine one way round!

Philip

[Philip Hall]

I have been able to measure a Hornby Castle this afternoon, and it comes out at 12.7mm over the cladding at the bottom of the firebox, just above the footplate. Assuming it should be about 17.7mm, that's quite a difference, which Craig correctly spotted. I was very surprised, and checked it three times, because it still doesn't look that obvious to me; I had the Russell book with me and found myself trying to see where they'd modified the curves. On the right hand side, it's really not apparent because of all the plumbing and the reversing rod there. On the left hand side, it could be disguised by a fire iron tunnel which many (the late ones?) seem to have had, or conveniently ignored.

Perhaps there are several design teams working on Hornby engines, because although the basic mechanicals are the same, there are often detail differences in how certain parts are manufactured. Neither a too wide or too narrow firebox would seem to be necessary, as the motors are not that wide now, easily fitting into both Castle and 28/38XX fireboxes, so why they should not be right is a mystery. The Castle has beautifully cast crossheads and slidebars (the latter are not far off the correct width), whereas the 28/38s have cast crossheads but only thin etchings for the slidebars.

It's still a wonderful model!

Philip

[HowardGWR]

I have not got a Hornby Castle in front of me as Philip has, but point out that a five mm difference is 'only' 2.5 mm each side. I don't suppose you inadvertently transposed 12.7 for 17.2 Philip? A 12.7 width would make it narrower than the frames (should be 16mm in accurate 4mm scale, appreciated that Hornby are modelling at 3.5 mm scale in that area , so 14mm). What are the frame /footplate dimensions on the Hornby, may I ask?

Given the trapezoidal tapering shape of the Swindon firebox, visually the important factor is the extent to which the cladding representation is seen to widen from the cab forwards to the join with the barrel cladding. I have seen models that did not look sufficiently tapered in this respect. We must remember that the frame inside width is just over 4 ft so the lower firebox beneath the frame has to fit that dimension, if one is going to model any of that. Not even Guy Williams did much between the frames IIRC (think two sets of Walschearts valve gear) and those items are far more visible.

By the way, in 4 mm dead scale that leaves just some two thirds of a mm between frames and wheels!

A correction to my earlier post in that by reviewing actual measurements in ft and ins, given on drawings, it shews that the footplate is 8ft 8ins wide (so indeed Hornby at 35 mm on my Saint are fine). I was falling into the trap of measuring the diagram pictures in books instead of reading the actual words and numbers on the drawing.

If it looks right it is right IMO. It's more important not to have a 1925 era representing model having G badge W on the tender ( I see that type of error often at shows).

[Philip Hall]

I haven't got a Castle in front of me any more, as I actually measured it in a cafe whilst its owner and I were having coffee! So I can't check anything more until the engine eventually comes back to me for conversion. But I measured the firebox three times and it was definitely 12.7mm. I'm still surprised that it looks OK with that discrepancy.

A more important thing to attend to will be the outside valve rockers; Hornby's narrow for 00 frames make the linkages look very odd and that will have to be addressed with packed out dummy frames, which is a pity and there is some very nice detail work there above the bogie.

Philip

[rule55]

It's a bit tricky to measure the width of the firebox because of the presence of the fire iron tunnel on the left hand side so I've measured the footplate width and then the distance between the outside of the footplate and the bottom of the firebox on the right hand side just forward of the rear splasher. This is what I've come up with; width of footplate = 34.15 (btw approx 0.5mm underscale if it's 8'8") distance between footplate edge and firebox 8.6mm. So, assuming the firebox is centrally located, that should give us 34.15 - (2 x 8.6) = 16.96mm which is fairly close to the quoted width of the prototype.

I'm a bit perplexed, have I measured the firebox in the wrong place?

[Philip Hall]

Egg on face time, I'm afraid. I've been measuring the Castle using a pair of outside calipers and measuring the difference between 'closed' and 'open' if you follow me, completely forgetting the fact that they are pivoted at the top and that the distance between the points decreases as you get nearer the pivot point! I really should know better after all these years...

I am sure now, having checked the 38XX the same way as Tony did on his Castle, that he is correct and that the firebox is correct which is why it doesn't look wrong. Thank you to Tony for pointing the way to a correct result. I think this probably proves the old adage "if it looks right...!"

Now I shall keep my head down and return to the 38XX, so that I can post the photo I promised on here a few days ago.

Philip

[rule55]

Philip,

If truth be told, the only reason I measured the firebox the way I did was because I couldn't lay my hands on a pair of outside calipers (I'd even started searching "Moore & Wright" on ebay in an attempt to correct this!) A lucky break for me by the sound of things...

I'm looking forward to seeing a photo of the 38XX.

All the best,

Tony

[HowardGWR]

Philip (and Tony)

Thanks very much for taking that trouble, I was beginning to doubt my sanity (Mrs H has had no doubts on that score for a long time).

I have managed to find a drawing of the number 1 boiler in the first Michael Rutherford book on the two cylinder engines which illustrates the shapes of the firebox in plan view on page 24 of the misnamed 'Halls...etc at Work'. The drawing appears to shew the firebox tapering in towards the rear at footplate level, so that there is a small gap between it and the top of the frame by the time it reaches the cab spectacle plate. The number 8 boiler will have the same shape I am sure, but I can't find an appropriate drawing for that.

That had not been a visible issue to me previously and of course the splasher fills the gap on the larger wheeled engines, so you can't see it. I assume the rear splashers are shaped in order to follow the taper. It may be this element that some producers get a bit wrong? On a small wheeled engine, one would see the footplating filling the gap to the cladding, behind the splasher, I assume. What do Hornby shew on the 28xx?

If I am wrong on this. please shoot me down, it's all fascinating stuff. There's probably a preservation workshop photo somewhere that tells all. I wish I was not so far from Didcot or Tyseley.

Modelling 'bent engines' as a LNER colleague once described them to me, is a subtle business, so an extra reason for leaving it to Hornby. Just a pity about the HO scale lower bits! Regards, Howard

[Philip Hall]

On the 38XX the firebox base does indeed taper very slightly towards the cab, as you correctly surmise it should. The splashers, such as they are on a 28/38, do butt up to the firebox. As I said, I no longer have the Castle but seen no reason why that should not also. Why the 38/28 is a little wide here is not clear.

Philip