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 Post subject: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 13:35 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
Many readers of this forum will be aware that the former GWR No 2 steam breakdown crane is currently out of service at the ESR, where steps are underway to try to return it to an operational condition. I thought that it might be of interest to some to hear what is happening, so I have started this thread as a form of "blog" to record progress.

A fairly full account of the history of this very important crane can be found on the "Selected Chronicles" page of the BDCA site (http://www.bdca.org.uk/gwr2.html) so I don't need to say much here, but the last time it operated under its own steam was in August 1989 at Goodrington, South Devon in the ownership of the Dart Valley Railway.

The crane was sold to the present owner in 2004, and the intervening fifteen years of storage, decay, and tinkering by well-intentioned preservationists had not been kind to it. When it came out of service, the boiler was in need of minor repairs, and to facilitiate these it had been removed from the crane. Unfortunately it was then mislaid (yes, it is possible to lose a crane boiler!), and one of the first priorities facing thenew owner was to locate and recover as many off the missing parts as possible.

The boiler, was eventually tracked down to Allely's haulage yard in Studley, Warwickshire, and with the co-operation of that well-known and respected haulier was returned to Cranmore. Most, but not all, of the other missing parts were also subsequently located and recovered. The following parts are still missing, and I should be very grateful for any information leading to their recovery:-

1) one clack valve and a "Y" shaped casting to fit two clacks onto a single port on the boiler. These were removed whilst the crane was at Buckfastleigh; the clack may have been reused on a GWR loco (it is a standard early 20th century GWR backhead clack), but the casting was known to have spent years 'under the bench' in the workshops, bet then vanished. If it still exists, its return would be a source of great joy to the crane's owner! If anyone knows of a GWR backhead clack that might be available, I would also be grateful to hear about it.

2) One makers plate, one plate with slewing clutch operating intructions, and a weight plate off the crane and another of the jib runner. These were probably removed for safe keeping whilst the crane was in store at Swindon between 1990 and 1995 but have since been lost. They are unique to the crane, and any information leading to their recovery would be appreciated beyond words.

3) One pair of number plates for the No 2 crane. These were removed sometime prior to the crane being taken out of service by BR(W) and haven't been seen for over 40 years, but they were probably kept as souvenirs so may still exists.

So there are still some parts missing, but generally enough parts have been recovered to allow the crane to steam - and lift - again.

The next post will be about boilers.


Comments and replies welcome!

Roger Cooke.


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 14:09 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
As promised, boilers. A bit of history first:-

During its working life with the GWR and BR(W), No 2 crane has had at least two different boilers fitted; or more accurately that should be two different types of boiler fitted.

When built, the crane was fitted with an obscure design of boiler built by E. R. & F. Turner of Ipswich, a type which was used on GWR No 2 of 1908, LNWR MP7 of 1910, and GWR No 3 of 1911, all 36-tonners and all generally very similar. The Turner boiler was of the vertical type, but with horizontal firetubes and a rear-projecting smokebox, operated at 80 PSI, and by all accounts was complex to build and maintain and generally not much use! The design saw limited use and during the First World War the firm ceased making boilers altogether to concentrate on the production of war materials and never resumed.

Attachment:
turner boiler small.jpg
turner boiler small.jpg [ 186.45 KiB | Viewed 21997 times ]


By 1917 the GWR had built at least one, and possibly as many as three, replacement boilers at Swindon of a more conventional design, designed to be interchangeable with the Turner boilers in Nos 2 and 3 cranes and with the Spencer Hopwood boiler in the Stothert and Pitt 36-ton crane No 1. These boilers were vertical firetube, dry head, boilers operating at 100 PSI, and were very simple and probably quite reliable. even though by 1917 they were an old fashioned and obsolescent design (by 1917 the overwhelming advantages of the Spencer Hopwood cross-tube boiler has been established, especially in steam cranes, and it is something of a mystery why the GWR didn't use this type. It may be that the GWR was reluctant to licence the design, or perhaps it was easier for Swindon to build a simper design, or possibly the pressures that WW1 was placing on the GWR and Swindon Factory justified the construction of a simpler boiler; the reasons will unfortunately probably never be known).

These boilers were used in preference to the Turner boilers, but at least one Turner boiler was retained as a spare - the most recent known photo of either No 2 or 3 with a Turner was taken c. 1965 (showing No 3 crane, based at Newton Abbott, working at Heathfield). Both cranes retained the distinctive cab sheeting mandated by the Turner smokebox to the end. The boiler that was fitted to No 2 when it was sold by BR(W) is a Swindon VFT boiler.

As mentioned in the first post, this boiler had actually been misplaced when the crane was bought by the present owner, and was eventually located in Warwickshire. After it was recovered to Cranmore, and thorough examination was carried out, a number of significant defects were found. It was known that the boiler would have some faults since this was why it was removed. The main problems were:-

1) The outer wrapper was severly wasted in the vicinity of all the mudhole openings, due to prolonged leakage. In addition, several of the openings had been built up with weld (in a rather cack-handed way) which had resulted in the plate deforming. To rectify this at the very least, an area of plate about 12" square would have to be cut out round each mudhole and replaced with new plate.

2) At some stage the boiler had been dropped onto the lower gauge glass boss resulting in the boss being pushed about 1/8" into the boiler with a clearly visible dent on the plate around it (it must have been quite an impact)! Although the boiler had been steamed with this dent, it was not felt that this should be allowed and the dent was considered to need rectifying. The repair options include appling heat and jacking force inside the boiler in the hope that it would straighten, or cutting a section of plate out and replacing it. The latter repair scheme would be complicated by the proximity of the compensating ring for the manhole, which would have to be removed to allow the plate to be welded in, then replaced afterwards.

3) The skirt was severly wasted and would require complete renewal (although on this boiler it is a bolt-on skirt making this technically simple).

4) All the usual other overhaul tasks such as retubing would also be needed.

All-in-all, it was highly likely that the sensible approach would be to replace the outer wrapper in its entirety with an all-new welded wrapper. Whilst not a difficult task, this was outside the scope of the funding available, and as a result the boiler overhaul had to be put on hold pending a lottery win, large inheritance, or other financial miracle or change of circumstance.

The boiler problems did not prevent other work being carried on, and many parts, such as the bottom block, turbo generator, lubricators, etc., have been overhauled in the meantime.

Next... more boilers, and things take a turn for the better.


Comments and replies welcome!

Roger Cooke


Last edited by Roger Cooke on 18 Apr 2011, 15:31, edited 1 time in total.

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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 14:43 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
After discovering the full extent of the work needed on the 1917 Swindon VFT boiler, time passed without any breakthrough. No bequests, no grants, no financial or other miracles meant that the boiler remained as the biggest impediment to the overhaul. In 2010 however things unexpectedly took a turn for the better.

In April 2010 I learned at very short notice that the former SR 45-ton crane DS1560 was to be scrapped (for reasons which were complex and not appropriate to go into here). Knowing that this crane had a good Spencer Hopwood boiler, several hours were spent in frantic phone calls to the former owner of the crane and the metal recycler to whom it had been sold. The outcome of this was the purchase - sight unseen - of the boiler complete with fittings and one or two other parts from the crane (these sundry parts included some for use on No 2 and also three other heritage cranes). Credit and thanks are due to both the former owner of DS1560 for enabling this to happen, and more especially to the good people at Simms Metal Management of Halesowen, without whose help it would not have happened.

Eventually, but only after a lot more water flowed under the bridge and with complications and excitement which may one day - but not yet - be told, the boiler arrived at Cranmore late one wet afternoon.

Attachment:
P5120957_r1.JPG
P5120957_r1.JPG [ 161.65 KiB | Viewed 21995 times ]


It may look a bit decrepit, but it is a better and more modern design of boiler, and on superficial examination in pretty good condition. The boiler was move to the workshop area, and the cladding and grate removed to allow a more thorough exam.


Comments and replies welcome!

Roger Cooke


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 15:15 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
The stripping of the cladding, grate, and few remaining fittings from the boiler was carried out rather hurriedly since John Glaze was due at Cranmore to do a boiler exam on one of our locos and it seemed an ideal opportunity to get him to give the "new" boiler a preliminary once-over without having the cost of an special trip.

No major problems were discovered during the stripping procedure. Fortunately the original asbestos blanket lagging had long ago been replaced with Rockwool, so there were no asbestos issues. Anyone who has not tried removing or fitting the mahole doors on a boiler of this kind will be astounded at how heavy they are - it is almost as much as one person can do to lift one, let alone manoeuvre in in or out of the door aperture! All the mudhole lids were missing (not a huge problem), fortunately all the three big doors are present and in reasonable condition. The grate is well used but sound. The ashpan has clearly had a huge bash when the boiler was lifted out of the crane, but this is a simple repair. Most of the plain tubes have rotted to the extent that daylight is visible through them, but all the plain tubes would be renewed as a matter of course. The stay tubes look reasonable. So far so good!

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P5270969.JPG [ 178.54 KiB | Viewed 21995 times ]

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P5270979.JPG [ 186.5 KiB | Viewed 21995 times ]

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P5270977_r1.JPG
P5270977_r1.JPG [ 148.05 KiB | Viewed 21995 times ]


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 15:20 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
A few more photos:-

This is the view inside the boiler, with the steam outlet to the manifold and safety valves visible.
Attachment:
P5270974.JPG
P5270974.JPG [ 161.53 KiB | Viewed 21995 times ]


After one quick visit to the teapot, this was the disturbing scene I found when I came back out. Fortunately I couldn't find any other body parts, so there wasn't much evidence to dispose of!
Attachment:
P5270967_r1.JPG
P5270967_r1.JPG [ 177.11 KiB | Viewed 21995 times ]


Comments and replies welcome!

Roger Cooke.


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 15:55 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
John Glaze gave the boiler the once-over, and pronounced that it was essentially very sound and a good overhaul prospect. It would require (as a minimum) the following:-

1) Thorough clean (pressure blasting or needlegunning) inside and out
2) When clean, a thorough exam with NDT where applicable
3) Skirt repairs
4) All plain tubes replaced
5) Stay tubes examined and NDT'ed and replaced where applicable
6) All fittings overhauled
7) The ashpan repaired
8) The usual hydraulic and steam tests.

And probably a few other things I have temporarily forgotten as I write this!

In addition, any other defects discovered during the above would need rectifying, but overall it is a better prospect than Swindon VFT requiring less work to overhaul, as well as being technically a better boiler. It is also pressed to 120 PSI rather than 100 PSI, which has further advantages when in service.

However, before the overhaul could begin in earnest there was one very important question that had to be answered - would it actually fit in the crane?

DS1560, the crane from which the boiler came, was one of six built in 1939 as an war emergency precaution for clearing air raid damage. These six (more fully described elsewhere on this site) were built to conform to the British composite loading gauge and were designed to run anywhere in the UK, including the Hastings line. GWR No 2 was built to the GWR standard loading gauge of the early 20th century, and is, by comparison, huge! It is taller that most GWR mainline locos as built, and is certainly out of gauge for the Network Rail main line (when we shunted the crane through the workshop at Cranmore some time ago we had to cut a notch in the doorframe to allow the jib-head to fit through, despite the doors being tall enough to accomodate any GWR loco). On the face of it therefore, there should be no problem.

However, on DS1560 the boiler sits on a steel plate perhaps 1" thick which is about 3" above the carriage. On GWR 2 the boiler sits on a steel bed which is about 8" thick, which has a space underneath it (between it and the carriage) for the six ton kentledge to be fitted, so another 14" or so, making a total of nearly 2 feet above the carriage compared to 1560's 4". So it was far from certain that the boiler would fit.

Standing the Hopwood and VFT boilers side by side showed that the Hopwood was significantly taller. It was going to be close!

Attachment:
P6070986.JPG
P6070986.JPG [ 193.08 KiB | Viewed 21994 times ]

Attachment:
P6070984.JPG
P6070984.JPG [ 193.02 KiB | Viewed 21994 times ]


In the photos above, the VFT is on the right and the Hopwood on the left.

Only one way to find out if it will fit, and that will be in the next installment.


Comments and replies welcome,

Roger Cooke.


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 18 Apr 2011, 16:07 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
The only way to be sure if the boiler would fit was, of course, to lift it into place and try!

So the water tank was removed from the crane (in actual fact it was found that the only thing holding the tank on was the roof girder bolted to it - the securing brackets shown on the R&R drawings having been removed by the GWR at some time!) and the boiler was lifted into place. This also proved to be an opportunity to see if the Iron Fairy could lift the boiler high enough to get it into place, another thing that was far from certain, and allowed the boiler to be weighed, since at this time we didn't actually know how heavy it was. It turns out to be 2.4 tonnes (without fittings and doors, without the grate, but still with the remains of the tubes in place).

Fortunately the Iron Fairy could lift high enough, but only by rigging the boiler on a very short sling as shown:
Attachment:
P3111061.JPG
P3111061.JPG [ 156.99 KiB | Viewed 21994 times ]


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P3111063_r1.JPG [ 173.69 KiB | Viewed 21994 times ]


Attachment:
P3111064.JPG
P3111064.JPG [ 156.58 KiB | Viewed 21994 times ]


An exciting moment - the first time that No 2 has had a boiler in it for at least a decade - but does it fit?

Find out tomorrow, or whenever I post the next installment!


Comments and replies welcome!

Roger Cooke.


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 19 Apr 2011, 09:23 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
With the Hopwood boiler in position in the crane, it became possible to assess whether or not fitting it was going to be feasible.

As far as the diameter was concerned, there were no problems at all; in fact the initial impression, based on the fit of the floor plates of the footplate, was that it was quite a lot smaller in diameter than the VFT boiler:-

Attachment:
P3111068.JPG
P3111068.JPG [ 156.51 KiB | Viewed 21986 times ]


The photo above shows the boiler relative to the curve of the floor plate. The vertical pipe capped off on the right is the main steam pipe, the object on the floor just left of centre front is the water seperator for the exhaust, and the space on the left (where the chequer plate is) is where the water tank fits.

The gap between the floor and the boiler is interesting, since the VFT boiler and the Hopwood are in fact the same nominal diameter. The original Turner boiler was however larger in diameter and probably followed the line of the edge of the floor, so presumably all the time the crane was operated (for some 70 years) since the VFT boiler was first fitted there has been a gap just the right width to get your foot stuck in between the floor plates and the boiler!

As far as the height of the boiler was concerned, it was clear that it is going to be a very tight fit under the cab roof:-

Attachment:
P3111070.JPG
P3111070.JPG [ 151.96 KiB | Viewed 21986 times ]

Attachment:
P3111071.JPG
P3111071.JPG [ 140.86 KiB | Viewed 21986 times ]


The critical areas as can be seen in the photos above are the 'shoulders' of the boiler - the top of the uptake (which will ultimately get about 1" taller when the uptake liner is fitted) will stick through the hole in the roof, but the roof has to cover the shoulders. It looks as though the roof may need a bulge added, but in fact in the photos the boiler is standing on blocks approx 3" thick to clear the original hold-down studs on the foundation casting which were still present during the test fit, so it will drop and additional 3" or so. It will be very close one way or the other, but there is no doubt that it can be made to fit without any obvious change to the external appearance of the crane.

Fortunately at the ESR we have no restricted headroom clearances (except for the workshop doorways mentioned earlier), so it really doesn't matter if the crane ends up becoming a few inches taller.

Speaking of which, I mentioned earlier that the GWR loading gauge allowed the crane to be significantly taller than the War Emergency cranes of 1939. The photo below gives an impression of just how tall it is. The vehicle immediately behind the crane is a standard BR Mk1 CCT(Y), and beyond that is a BR(W)-built PASFRUIT D; notice how the crane towers over both!

Attachment:
P3111067_adj.JPG
P3111067_adj.JPG [ 130.06 KiB | Viewed 21986 times ]



Comments and replies welcome!

Roger Cooke.


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 19 Apr 2011, 14:36 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
Once we had established that it was going to be possible to fit the boiler in the crane, it was lifted out again to go into the workshop to allow the overhaul to begin.

As mentioned above, initially I hoped that it would be possible to replace only the plain tubes and leave the stay tubes alone, but after the plain tubes were removed it became apparent that several of the stay tubes would need replacing as well. Whilst the majority of these were in the centre of the firebox, where (in theory at least) they could be replaced without disturbing the firebox, it became clear pretty quickly that not only would it be difficult to replace those which had to be replaced, but that the remainder were not in much better condition and would not be far behind.

For those unfamiliar with the layout of the cross-tubes in a Hopwood boiler, the tubes are arranged to run across the firebox with a slight upward inclination. There are two tube doors, one on each side of the boiler, and each gives access to one end of one half of the tube nest. Each tube is fitted from the end with the door, so that in theory at least all the tubes can be fitted with the firebox remaining in the boiler shell. With the plain tubes this can be done without too much difficulty, although a special very compact tube expander is needed for the far end (where the is only a few inches of clearance between the tube end and the outer wrapper) but the stay tubes, of which there are ten distributed throughout the tube nest, are threaded at both ends and are seal-welded to the steel tubeplate. Apart from the stay tubes in the middle of the box, which are - just about - accessible from both tube doors, it is not possible to weld these with the firebox in the boiler. Generally the stay tubes last a lot longer than the plain tubes though, so replacing them is not considered a routine maintenance task.

So the question then became whether or not to remove the firebox and flue from the boiler shell. There are pros and cons to this:-

Pros - all the stay tubes can be replaced, replacing the plain tubes becomes a doddle, it becomes very much easier to clean the inside of the boiler and the outside of the firebox, and various other repairs become easier.

Cons - there is quite a lot of work in removing the rivets from the foundation ring, firehole door ring, and flue, and coaxing the firebox and uptake out of the outer wrapper, plus of course there is the need to refit, re-rivet, and caulk afterwards.

In the end, we concluded it would be a false economy not to replace all the stay tubes are this time (and the last thing we want is to have to do this all again in a few years) so the decision was made to remove the firebox and do a proper job. Besides, we are fortunate to have some really skilled boilersmiths in our workshop team at the ESR (in fact we have a really good workshop team) who just love hot rivetting!

With apologies for the camera shake, the photo below shows the complete tube nest before removal of any tubes, looking through where the grate would usually be fitted.

Attachment:
P3191077.JPG
P3191077.JPG [ 148.38 KiB | Viewed 21983 times ]


The next two photos show the view after the plain tubes have been removed, with just the stay tubes remaining in situ. Firehole door aperture at top left.

Attachment:
P3261089.JPG
P3261089.JPG [ 167.09 KiB | Viewed 21983 times ]


Attachment:
P3261081.JPG
P3261081.JPG [ 173.21 KiB | Viewed 21983 times ]


A closer view of the stay tubes. Deep pitting clearly visible, definitely a false economy not to renew these now.

Attachment:
P3261083.JPG
P3261083.JPG [ 165.68 KiB | Viewed 21983 times ]


Finally, the view through one of the tube doors showing the tubeplate and ligaments, fortunately in excellent condition, and the ends of six of the ten stay tubes.

Attachment:
P3261085.JPG
P3261085.JPG [ 170.02 KiB | Viewed 21983 times ]



Comments and replies welcome!

Roger Cooke


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 Post subject: Re: GWR No 2 overhaul
PostPosted: 19 Apr 2011, 15:07 
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Joined: 23 Dec 2010, 00:07
Posts: 337
Location: Poole, Dorset
It occurs to me that throughout this thread I have made several references to "Spencer Hopwood" boilers, and "Hopwood" boilers, but not all readers will be familiar with these.

The Spencer-Hopwood type of boiler was arguably the most successful compact vertical boiler of the steam era, with the last new boilers being made as recently (I believe) as the 1970s. The unique characteristics were the inclined transverse nest of waterfilled cross tubes, which ensure excellent circulation, and the central flue or uptake. The first boilers were constructed by the Spencer-Hopwood Company of Hitchin, Herts, and the design may be attributable to Arthur Lincolne Hitchcock-Spencer also of Hitchin, Herts. or may be the brain-child of "Hopwood", someone about whom little is presently known (Spencer is certainly named on several relevent patents, but it seems more likely that Hopwood had the original idea). This is an area which is presently being researched by various members of the BDCA, so hopefully before long more will be known.

The "Spencer-Hopwood" boiler, or as it was more commonly known, the "Hopwood" boiler, was, over the years, built by quite a number of different companies. The original firm of Spencer-Hopwood became part of Robert Stephenson and Hawthorns Ltd, and we know that Marshall, Sons and Co Ltd of Gainsborough were making Hopwood boilers in the 1920s.

The boiler from DS1560 was built in 1939 by Cochran & Co. of Annan, which may intially have been an arrangement brought about by wartime circumstances, but certainly continued after the war. So the boiler for No 2 is probably more properly described as a Cochran-Hopwood boiler!

Incidentally, the firm of Cochran & Co of Annan still exists, albeit now as Bib Cochran, and has very kindly supplied me with copies of many of the original drawings for the boiler which they still have in their archive. Fantastic!

Below is a part of the original Ransomes and Rapier drawing of the Hopwood No 14 Squat boiler used on the LSWR 36 ton crane which became SR DS35 showing the general arrangement of tubes etc.

Attachment:
Hopwood boiler.jpg
Hopwood boiler.jpg [ 101.75 KiB | Viewed 21983 times ]



Comments and replies welcome!

Roger Cooke.


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