Wright writes.....

[lee74clarke]

Good Morning Tony,

I hope you and Mo are well? Can I ask a question regarding Thompson A2/3's please, or more specifically their boilers?

Did diagram 117 boilers always have a round dome, and diagram 118 always have streamlined domes? Would the dome always be in exactly the same position, or would any engineering changes mean slight repositioning? I'm sure this is an easy answer, but as with anything, you only know if you know.

With the information sources I have, 117 round / 118 streamlined seems to be the case, but I am piddling about renaming/renumbering a Hornby A2/3 and want to ensure it's somewhere near. 

My thanks in advance.

Edited January 28, 2022 by lee74clarke

[Barry Ten]

May I also ask a question about valve gear?

 

I'm currently setting up the gear on a Comet Princess chassis. With the other types I've done (Urie, Maunsell, Fowler and Riddles), it was easy to do one side then the other. With this type, the radius rod needs to go through a slot in the motion bracket, which is a single fold-up design covering both sides. As it stands, both sets of gear need to be set up at the same time as there's no obvious way to get the opposing crosshead and radius rod on if the other side is already fixed.

 

The bracket is meant to be bolted to a frame spacer. I can't see a straightforward way of separating it into two halves, as if I do that, then (apart from losing the bolt fixture) either half will be need to be soldered to the top edges of the frames, which doesn't feel like a particularly robust arrangement. Any suggestions, other than just biting the bullet and setting up both sides at the same time?

 

Al

[Tony Wright]

53 minutes ago, lee74clarke said:

Good Morning Tony,

I hope you and Mo are well? Can I ask a question regarding Thompson A2/3's please, or more specifically their boilers?

Did diagram 117 boilers always have a round dome, and diagram 118 always have streamlined domes? Would the dome always be in exactly the same position, or would any engineering changes mean slight repositioning? I'm sure this is an easy answer, but as with anything, you only know if you know.

With the information sources I have, 117 round / 118 streamlined seems to be the case, but I am piddling about renaming/renumbering a Hornby A2/3 and want to ensure it's somewhere near. 

My thanks in advance.

Good afternoon Lee,

 

We're both very well, thank you. I hope you and yours are, too.

 

All Dia. 117 boilers on the A2s and A2/3s had round domes (the one fitted to just one A2/2, 60505, had a streamlined cover). Any A1s which received 117 boilers had streamlined covers over the domes (even though what was underneath was a round dome, not a perforated steam collector). The only exception to this was 60153, which had a round dome cover. 

 

Dia. 117 boilers had the dome further forward than the streamlined ones of the Dia. 118 type. All A2/3s at some time in their lives had Dia. 118 boilers, though some reverted back to 117s, later. All the A1s and A2s started off with Peppercorn 118 boilers, but some later received the Thompson type. The two boiler types were fully-interchangeable among the four classes fitted with them.

 

Four A2/2s eventually received Dia. 118 boilers (60501/2/5/6).

 

Since all of this is off the top of my head, it might be wise to check (you may borrow the books if you wish).  

 

Interestingly, in Hornby's latest catalogue, they show 60502 as becoming available later this year, but it's got a 117 boiler (the same as 60505). It never received this type, neither did it ever get the backing plate between the sandbox fillers, or the cut-back handrails at the front. I assume it's just a 'graphic' as far as Hornby is concerned, though I hope it doesn't appear like this. I'm going down to Margate next month, so I'll ask Simon Kohler.

 

Regards,

 

Tony.  

[Tony Wright]

34 minutes ago, Barry Ten said:

May I also ask a question about valve gear?

 

I'm currently setting up the gear on a Comet Princess chassis. With the other types I've done (Urie, Maunsell, Fowler and Riddles), it was easy to do one side then the other. With this type, the radius rod needs to go through a slot in the motion bracket, which is a single fold-up design covering both sides. As it stands, both sets of gear need to be set up at the same time as there's no obvious way to get the opposing crosshead and radius rod on if the other side is already fixed.

 

The bracket is meant to be bolted to a frame spacer. I can't see a straightforward way of separating it into two halves, as if I do that, then (apart from losing the bolt fixture) either half will be need to be soldered to the top edges of the frames, which doesn't feel like a particularly robust arrangement. Any suggestions, other than just biting the bullet and setting up both sides at the same time?

 

Al

Good afternoon Al,

 

All my (split) motion support brackets are just soldered to the tops of the frames. 100s have never come loose! 

 

 

B1s.

 

 

 

A DJH 'Semi'.

 

 

And a V2.

 

Regards,

 

Tony. 

[lee74clarke]

7 minutes ago, Tony Wright said:

Good afternoon Lee,

 

We're both very well, thank you. I hope you and yours are, too.

 

All Dia. 117 boilers on the A2s and A2/3s had round domes (the one fitted to just one A2/2, 60505, had a streamlined cover). Any A1s which received 117 boilers had streamlined covers over the domes (even though what was underneath was a round dome, not a perforated steam collector). The only exception to this was 60153, which had a round dome cover. 

 

Dia. 117 boilers had the dome further forward than the streamlined ones of the Dia. 118 type. All A2/3s at some time in their lives had Dia. 118 boilers, though some reverted back to 117s, later. All the A1s and A2s started off with Peppercorn 118 boilers, but some later received the Thompson type. The two boiler types were fully-interchangeable among the four classes fitted with them.

 

Four A2/2s eventually received Dia. 118 boilers (60501/2/5/6).

 

Since all of this is off the top of my head, it might be wise to check (you may borrow the books if you wish).  

 

Interestingly, in Hornby's latest catalogue, they show 60502 as becoming available later this year, but it's got a 117 boiler (the same as 60505). It never received this type, neither did it ever get the backing plate between the sandbox fillers, or the cut-back handrails at the front. I assume it's just a 'graphic' as far as Hornby is concerned, though I hope it doesn't appear like this. I'm going down to Margate next month, so I'll ask Simon Kohler.

 

Regards,

 

Tony.  

 

We're all very well thank you.

I have several books with A2/3 details, so had assumed I was right (never assume) but thanks for clarifying. I think the possibility of streamlined domes covering the round dome, as per some A1's, was confusing me, but that's all much clearer now. That wasn't a practise seen on A2/3's then, just the A1's?

Thanks again, and hope to see you soon

Lee

[Tony Wright]

14 minutes ago, lee74clarke said:

 

We're all very well thank you.

I have several books with A2/3 details, so had assumed I was right (never assume) but thanks for clarifying. I think the possibility of streamlined domes covering the round dome, as per some A1's, was confusing me, but that's all much clearer now. That wasn't a practise seen on A2/3's then, just the A1's?

Thanks again, and hope to see you soon

Lee

That's right Lee,

 

The only locos with streamlined dome covers over the round domes of their 117 boilers were the A1s, and the solitary A2/2, 60505. Of course, not all A1s received Thompson boilers.

 

But ALCAZAR did, for a time...........

 

 

DJH kit, built by me and painted by Ian Rathbone. 

 

 

On Stoke Summit.

 

 

And for real, at Little Bytham in 1961 (after the station was demolished). 

 

 

The nearest I can get!

 

 

Another DJH A1 model of 60136, this time with a 118 boiler. Is this yours, Ray?

 

And a few A2/3 variants............

 

 

60500 in late '50s condition, still with Dia. 117 boiler (but only in four sections of cladding, only found on this loco and 511 - for a short time). Original rimmed chimney.

 

Built by me from a much-modified Crownline kit, and painted by Ian Rathbone.

 

 

More normal boiler cladding division on a 117 boiler.

 

Built by me from a DJH kit and painted by Ian Rathbone.

 

 

 

An A2/3 with a Dia. 118 boiler. 

 

Built by me from a DJH kit, and painted by Geoff Haynes.

 

 

And, finally, a Graeme KIng/Bachmann A2 conversion to produce an A2/3 with a 118 boiler. 

 

Conversion by Graeme himself, patch re-painted/weathered by me. 

 

Regards,

 

Tony. 

 

 

 

 

 

 

[Barry Ten]

Many thanks for the examples of motion brackets, Tony. I shall follow your examples.

[gr.king]

3 hours ago, Headstock said:

 

Good morning Tony,

 

your SEF W1 has the correct roof though, neither the Hornby or Hornby conversion have it right. At one time and due to it being erroneously flush, Hornby just painted the V shape on to the boiler cladding, on some more recent examples they no longer seem to bother painting it on and it is thus missing completely.

 

 

Just for clarity, do you mean that on the real A4s (some of which survive, but after many repairs) and on the rebuilt W1(which no longer exists so cannot be checked unless somebody has an excellent photograph) the V-front of the cab roof stood slightly proud of the boiler clothing, all the way to the tip of the Vee? 

Also, which ventilator bulge is correct in cross-section? Hornby's, with the arc of the bulge meeeting the flatter arc of the main roof at a flush joint, or the SEF version with a slight step at the edges?

If I'd had definite proof at the time of the conversion that the tip of the Vee should be slightly proud it would have been no great trouble to gently file the necessary part of the boiler to create the subtle step without spoiling the smooth lines of the boiler clothing. Raising the edges of the bulge too would instead have required an overlay, which could also have been added.

Hindsight...

[Iain.d]

On 23/01/2022 at 16:23, jwealleans said:

I remember seeing that WSM kit and being briefly tempted.... then I remembered how awful their C1 kit was.   I'll be interested to see how it turns out.

The build of my WSM 7 plank PO wagon is complete.

 

 

It wasn’t hard but it was certainly awkward.  The main brass is 20 thou thick and the part etched lines for the folds needed some heavy filing to open them up or the bends, when made, would never have been 90 degrees. Also, for the soldering everything needed to be done with the biggest bit I have, with the iron at max temperature, this of course meant that some bits became unsoldered as I tried to add other bits…

The only glued on bits are the axle boxes. The brass got so dirty – it literally tarnished before my eyes!

 

Rather than just solder the chassis side frames to the underside of the body, I decided to solder an offcut of brass between the chassis sides so I could get the axles all square and free running first, then I tack soldered the whole chassis to the underside of the floor.

 

 

I have no idea why a hole is etched through the drop side door – I’m aware when some wagons were re-purposed, holes were cut in the sides to prevent over filling with dense materials. I don’t think that’s the case here. Additionally, to my eye the proportions look wrong; it looks too short for its height (it's 64mm/16ft over the headstocks), other open wagons I have equal about 17ft/17ft 6in.  It’ll be finished in grey, with 3 link couplings, and added to my engineer’s train. And it needs some door banger stop things.

 

 

Did I enjoy the build? No, not really.  Would I buy/do another one? No….never…!

 

Kind regards,

 

Iain

Edited April 1, 2022 by Iain.d

[jwealleans]

I think that looks a decent result.  If another ever comes my way, I'll bear this in mind.

 

A 16' mineral must be to one of the earlier specifications - 1887, maybe?   I'd speculate that the hole in the door is supposed to be covered by a bang plate to prevent the V hanger wrecking the door in the absence of a door spring. 

[lee74clarke]

1 hour ago, Tony Wright said:

That's right Lee,

 

The only locos with streamlined dome covers over the round domes of their 117 boilers were the A1s, and the solitary A2/2, 60505. Of course, not all A1s received Thompson boilers.

 

But ALCAZAR did, for a time...........

 

 

DJH kit, built by me and painted by Ian Rathbone. 

 

 

On Stoke Summit.

 

 

And for real, at Little Bytham in 1961 (after the station was demolished). 

 

 

The nearest I can get!

 

 

Another DJH A1 model of 60136, this time with a 118 boiler. Is this yours, Ray?

 

And a few A2/3 variants............

 

 

60500 in late '50s condition, still with Dia. 117 boiler (but only in four sections of cladding, only found on this loco and 511 - for a short time). Original rimmed chimney.

 

Built by me from a much-modified Crownline kit, and painted by Ian Rathbone.

 

 

More normal boiler cladding division on a 117 boiler.

 

Built by me from a DJH kit and painted by Ian Rathbone.

 

 

 

An A2/3 with a Dia. 118 boiler. 

 

Built by me from a DJH kit, and painted by Geoff Haynes.

 

 

And, finally, a Graeme KIng/Bachmann A2 conversion to produce an A2/3 with a 118 boiler. 

 

Conversion by Graeme himself, patch re-painted/weathered by me. 

 

Regards,

 

Tony. 

 

 

 

 

 

 

Thank you Tony, all very helpful and much appreciated

 

Best Regards,

Lee

[Headstock]

1 hour ago, gr.king said:

 

Just for clarity, do you mean that on the real A4s (some of which survive, but after many repairs) and on the rebuilt W1(which no longer exists so cannot be checked unless somebody has an excellent photograph) the V-front of the cab roof stood slightly proud of the boiler clothing, all the way to the tip of the Vee? 

Also, which ventilator bulge is correct in cross-section? Hornby's, with the arc of the bulge meeeting the flatter arc of the main roof at a flush joint, or the SEF version with a slight step at the edges?

If I'd had definite proof at the time of the conversion that the tip of the Vee should be slightly proud it would have been no great trouble to gently file the necessary part of the boiler to create the subtle step without spoiling the smooth lines of the boiler clothing. Raising the edges of the bulge too would instead have required an overlay, which could also have been added.

Hindsight...

 

Good afternoon Graeme,

 

the 'ventilator bulge' was a separate construction that could be unbolted from the rest of the cab roof. On both the W1 and A4 it was proud of the boiler cladding, though it conformed to the shape whilst still forming the distinctive V. It's not a criticism of your work, rather noting that all three models have different compromises that diverge from the real thing. The Hornby model doesn't bother to physically represent the V, rather it is painted on. The lip of the V is visible above the cladding band on crop of 60700 shown below. The lack of the V is actually more visible on the Hornby model from above, especially when it has been forgotten about in the painting.

 

 

I have also added an A4 for completeness.

 

 

 

 

 

 

 

 

Edited January 28, 2022 by Headstock
Add an A4.

[PupCam]

On 26/01/2022 at 20:57, Chas Levin said:

What I find incomprehensible is anyone not finding things to do that really interest them.

 

You and me both!   I just cannot comprehend "having no interests".     My problem is that I can easily get interested in almost anything (as long as a ball and running or walking about is not involved).

 

I remember many years ago having just read Chris Pilton's lovely tome "Cottage Modelling for Pendon" how I developed a fascination for the brick bonds used in the construction of walls.  Before that my only awareness of brick walls was falling off of or crashing into them!   I can find interest in almost anything particularly if it has a technical / engineering bias much to the dismay of my long suffering wife.   That might explain the grubby hands from wrangling old motorcycles then.

 

19 hours ago, Tony Wright said:

Linking railway modelling/photography, one thing I'm trying more of is to take shots of the same train, but with different lenses........

 

As with this pair..............

 

35mm at F29.

 

 

60mm at F45.

 

Just different............

 

For me the sign of a good model is the ease of suspension of belief that the model is just that and not "the real thing" whether that be architectural, railways, aeroplanes, ships, cars etc etc.  That also explains why I have no interest in "Fantasy" (rather than freelance) railway models and irrespective of the quality of workmanship & skill involved (which is something I have deep respect for) and tend to walk straight past in say the exhibition setting.

 

I think the same also applies to model photography.   Both those shots are very good, the workmanship and balance in standards of workmanship of the subject is of course without question, but by far the better photograph for me is the first of the pair.   That is because it or it's ilk could easily be "found" (particular if converted to monochrome) in any number of books prototype photographs.     With absolutely no disrespect at all, the second photograph just shouts "model railway" to me but I can't for the life of me put my finger on why!  

 

But as I've said before, what do I know!

 

Alan

[Tony Wright]

7 hours ago, gr.king said:

 

It certainly did when I handed it over to Roy. I know that he subsequently fitted Brassmaster main frame overlays to control the behaviour of the axles more tightly, but nothing was said to me about any change of bogie.

Thanks Graeme,

 

I think it is the Hornby bogie, judging by its front end. 

 

To be honest with you, when I built my W1s I never bothered checking the bogie's length. For the first one (for the original Stoke Summit and Leighford), I 'stretched' a Wills A4 on top of a scratch-built set of frames, using a Jamieson A3 bogie. For the second W1 (after the first was sold and went to Germany), I just used the SEF one supplied. 

 

It was only on checking the principal dimensions for my review of the Hornby W1 that I noted the extra length of the W1's bogie. Looking at those three pictures again, it is (just) noticeable. 

 

One thing I didn't check (forgetfulness) were the differences apart of the boiler cladding bands on the W1 compared with an A4. From memory, when I did my first adapted-from-a-Wills-A4 (in the late-'70s), I seem to remember that the W1's boiler bands were not exactly the same distance apart as on an A4 - nearer the firebox they were slightly further apart (not by much), meaning was it not just an A4 boiler with a longer firebox? Was it a slightly longer boiler as well? I seem to recall I had to make the firebox (which I scratch-built from brass) a bit longer to compensate. I can't find my drawing source right now (it was not Isinglass), and my memory isn't what it was. It could be that the drawing I used (which was in a book of drawings published in 1947) was wrong. It wasn't by Roche, but drawings of that time could be notorious. 

 

Your conversion seems to have the proportions spot-on.

 

Regards,

 

Tony.  

[MikeTrice]

Being aware of the previous conversations regarding the cab "V" on A4 I took this photo of Mallard at the NRM:

[Tony Wright]

1 hour ago, PupCam said:

 

You and me both!   I just cannot comprehend "having no interests".     My problem is that I can easily get interested in almost anything (as long as a ball and running or walking about is not involved).

 

I remember many years ago having just read Chris Pilton's lovely tome "Cottage Modelling for Pendon" how I developed a fascination for the brick bonds used in the construction of walls.  Before that my only awareness of brick walls was falling off of or crashing into them!   I can find interest in almost anything particularly if it has a technical / engineering bias much to the dismay of my long suffering wife.   That might explain the grubby hands from wrangling old motorcycles then.

 

 

For me the sign of a good model is the ease of suspension of belief that the model is just that and not "the real thing" whether that be architectural, railways, aeroplanes, ships, cars etc etc.  That also explains why I have no interest in "Fantasy" (rather than freelance) railway models and irrespective of the quality of workmanship & skill involved (which is something I have deep respect for) and tend to walk straight past in say the exhibition setting.

 

I think the same also applies to model photography.   Both those shots are very good, the workmanship and balance in standards of workmanship of the subject is of course without question, but by far the better photograph for me is the first of the pair.   That is because it or it's ilk could easily be "found" (particular if converted to monochrome) in any number of books prototype photographs.     With absolutely no disrespect at all, the second photograph just shouts "model railway" to me but I can't for the life of me put my finger on why!  

 

But as I've said before, what do I know!

 

Alan

I agree entirely Alan,

 

The second shot (using the Nikon 60mm Micro - not Macro - lens) does look more model railway-like. It might be because of the greater clarity that 'specialist' lens gives.

 

Anyway, the first in B&W........

 

 

What I like about this shot is that it shows (almost) the full width of Little Bytham, which has plenty of space to 'breath'.

 

Even modest stations often sprawl when their full extent is considered in model form. It's not just length, but breadth which must be taken into account for realism.

 

Of course, the 60mm Micro lens doesn't give that breadth.

 

 

Though it does give relentless depth of field!

 

Regards,

 

Tony. 

 

 

Edited January 28, 2022 by Tony Wright
typo error

[PMP]

1 hour ago, Tony Wright said:

I agree entirely Alan,

 

The second shot (using the Nikon 60mm Micro - not Macro - lens) does look more model railway-like. It might be because of the greater clarity that 'specialist' lens gives.

 

 

Of course, the 60mm Micro lens doesn't give that breadth.

 

 

Regards,

 

Tony. 

 

 

I think it’s likely to be the telephoto effect, it highlights elements in the image that aren’t following the regressing perspective lines, eg the bottom of the cab, and the tender base level stand out for me and then some of the rear coaches don’t look to be sitting ‘right’.

They may in fact be right, but the compression in the image either accentuates or distorts those lines to highlight those elements. In pic1 you really have to look for the same effects.

Edited January 28, 2022 by PMP
Add pic

[micklner]

32 minutes ago, PMP said:

I think it’s likely to be the telephoto effect, it highlights elements in the image that aren’t following the regressing perspective lines, eg the bottom of the cab, and the tender base level stand out for me and then some of the rear coaches don’t look to be sitting ‘right’.

They may in fact be right, but the compression in the image either accentuates or distorts those lines to highlight those elements. In pic1 you really have to look for the same effects.

On the same picture.

The Loco's Footplate and the Cylinder (which is even bulging out more at the top from under the Footplate), look like they are leaning to the left at the front end , and then the Footplate is  slightly leaning  to the right as it goes towards the Cab. The Tender then is higher at the rear than at the front . Bizarre.

[gr.king]

2 hours ago, MikeTrice said:

Being aware of the previous conversations regarding the cab "V" on A4 I took this photo of Mallard at the NRM:

 

Looks like the central portion stands proud of the boiler clothing by no more than one thickness of metal, the roof sheet being bolted down directly onto the the clothing. Will it be as much as 5/8"? In 4mm scale say 0.008" max?

 

Did you happen to get a picture to confirm the tail end shape of that bulge housing the safety valves and sliding vents too please?

[MikeTrice]

Like this?

[MikeTrice]

Another one from a different angle:

[Headstock]

6 hours ago, Iain.d said:

The build of my WSM 7 plank PO wagon is complete.

 

 

It wasn’t hard but it was certainly awkward.  The main brass is 20 thou thick and the part etched lines for the folds needed some heavy filing to open them up or the bends, when made, would never have been 90 degrees. Also, for the soldering everything needed to be done with the biggest bit I have, with the iron at max temperature, this of course meant that some bits became unsoldered as I tried to add other bits…

The only glued on bits are the axle boxes. The brass got so dirty – it literally tarnished before my eyes!

 

Rather than just solder the chassis side frames to the underside of the body, I decided to solder an offcut of brass between the chassis sides so I could get the axles all square and free running first, then I tack soldered the whole chassis to the underside of the floor.

 

 

I have no idea why a hole is etched through the drop side door – I’m aware when some wagons were re-purposed, holes were cut in the sides to prevent over filling with dense materials. I don’t think that’s the case here. Additionally, to my eye the proportions look wrong; it looks too short for its height (it's 64mm/16ft over the headstocks), other open wagons I have equal about 17ft/17ft 6in.  It’ll be finished in grey, with 3 link couplings, and added to my engineer’s train. And it needs some door banger stop things.

 

 

Did I enjoy the build? No, not really.  Would I buy/do another one? No….never…!

 

Kind regards,

 

Iain

 

Good evening Ian,

don't give up, it's a nice build of one of the most common types of wagon built in this country but not seen a lot on model railways. However, it is not the most likely type of wagon to be found in an engineers train, especially in your time period. It's a turn of the century PO coal wagon, there was a mass culling of such  wagons in the early years of Nationalization, you might consider departmental black? 

Believe it or not, 16' wagons of this type made up the bulk of the PO mineral wagon fleets, easily outnumbering the later 1923 17' RCH design. The results of the Great depression stopped the 1923 design usurping the older shorter wagons. The 17' 6'' length was usually reserved for the later types of General merchandise wagons.
 

[robertcwp]

On 27/01/2022 at 21:45, Tony Wright said:

I popped over to see Retford today. 

 

Thanks for your hospitality, Sandra.

 

I took some pictures, including............

 

 

A modified Hornby A4 on the Down Talisman.

 

That is one of the best photos of Retford that I have seen. It really conveys the size of it all and the fact that it is essentially true to scale. 

[robmcg]

On 28/01/2022 at 10:45, Tony Wright said:

I popped over to see Retford today. 

 

Thanks for your hospitality, Sandra.

 

I took some pictures, including............

 

 

A modified Hornby A4 on the Down Talisman.,,,,,

 

What a very fine photograph of a stunning model railway.

 

Your influence on many readers Tony must be very great. I have just bought a full frame digital camera and am in the process of finding which lenses and settings might permit me someday to aproach the standard you achieve, the 'gold standard', with your Nikon and various lenses.

 

I have bought, for any who are interested, a full-frame Canon RP 26MP mirrorless camera and a couple of basic lenses, but even these weren't particularly cheap.  I do love cameras though, so messing around with them and RTR models will bring much pleasure, and quite probably a degree of bemusement and frustration. Untangling the intricacies of modern camera menu systems and endless options for settings is something of a skill, separating what matters from what doesn't, don't get me started! .

 

Thank you for setting such an admirable standard.

 

 

[SuperD]

12 hours ago, Barry Ten said:

May I also ask a question about valve gear?

 

I'm currently setting up the gear on a Comet Princess chassis. With the other types I've done (Urie, Maunsell, Fowler and Riddles), it was easy to do one side then the other. With this type, the radius rod needs to go through a slot in the motion bracket, which is a single fold-up design covering both sides. As it stands, both sets of gear need to be set up at the same time as there's no obvious way to get the opposing crosshead and radius rod on if the other side is already fixed.

 

The bracket is meant to be bolted to a frame spacer. I can't see a straightforward way of separating it into two halves, as if I do that, then (apart from losing the bolt fixture) either half will be need to be soldered to the top edges of the frames, which doesn't feel like a particularly robust arrangement. Any suggestions, other than just biting the bullet and setting up both sides at the same time?

 

Al

Hi,  I've just done my first loco with valve gear, a Comet chassis Scot and finished up with this very same problem.  A good bit of chunnering and a lot of patience later I managed it, but it's two halves next time I think.