Stoker

Thanks for the replies chaps. I've been working on a design based around the Bachmann Percy/Greg chassis which has a 31mm wheelbase and the wheels appear to be approx 14mm. It sounds like the Hornby 0-4-0 chassis might be a good alternative as 33mm x 16mm is very close. I'm hoping to snag a donor soon so that I can confirm the dimensions and get building. I'm particularly interested to see if I can figure out some ways to upgrade the chassis for slower running, perhaps with a motor swap and some better gears. Here's a rough draft. I'm quite happy with how it's turned out.

Yes you're right it was oil fired, I forget about that, so technically not a coal fired kiln although still a traditional pan kiln in every other respect, and you're correct that it closed in 1991. The heat from the oil burner passed through the old furnace and under the pan, which dried the clay in the traditional way without any mechanical assistance (apart from the digger). Quite remarkably, the works was operated by English China Clays, and was the last pan type dryer the company operated. It's quite incredible to think that this dinosaur outlived the technically more modern 1939 built Rockhill rotary, and ww2 built Collins rotary and Drinnick Old Cooperage Buell. This photo taken in 1992 one year after closure shows Lower Bostraze dry from outside with it's distinctive square brick stack, the settling tanks are also visible. The equipment on the left resembling shelves are triple deck screens, very outdated by the time this photo was taken, but in the 30's through to the 60's these were quite commonly used to classify clay to the desired particle size distribution prior the use of more sophisticated refining plant such as centrifuges, floatation cells, hydrocyclones, and hydroclassifiers. Lower Bostraze was not within pumping distance of a clay refinery, and it's 5000 ton per annum output precluded building one locally, so it had to use this more primitive method to the bitter end. If these were not used, there was no way to separate coarse from fine grade clay, and also some clay would be so fine that it could actually pass through the filter press cloth and be lost in the filtrate. This undersized clay was pumped back to a tank where it would be dosed with a chemical called a flocculant, which encouraged the clay to form into larger particles, and then pumped back through the screens to form a closed circuit. This CCHS photo on the interior of Lower Bostraze shows the small digger used to move dried clay from the pan to the linhay. The travelling bridge with wagon can be seen being moved by a worker, and I believe the item on the wagon is a quick-attach implement of some kind. This photo, credit to Jim Casley son of the last manager of the works, shows the oil burners in the furnace.

Could you possibly give dimensions for this loco? I have a project in mind and I'd be interested to do something similar. Wheelbase, driver diameter, width, length, height, etc. would all be very useful.

In the early 1990's only two coal fired drys remained; Great Wheal Prosper dry at Carbis Wharf, and another (not rail served) deep in the west near St Just. By that time, manual labour had almost completely been eliminated from the once dreaded "old way". Mechanical stokers fed the furnaces (a circa 30's to 50's innovation), a filter press house replaced the wagon tanks (these came in early 1900s), and the role of men shovelling dry clay off the pan was replaced by a small kubota excavator which rode on one of the two travelling bridges (introduced around the 1980s). Lord Falmouth's "underdog" clay company Goonvean & Rostowrack owned "Prosper" dry, and leased a single Tiger wagon from the fleet that Tiger had originally allocated entirely to ECC. I believe this ended up being the last white tiger, the last freight out of Carbis, and the only air braked wagon to receive clay dried by coal. A photo of the mechanical stoker at Great Wheal Prosper dry, Carbis. Coal came in down the chute into a small hopper, which fed into the tube seen below. The tube contained a spiral auger which fed the coal into a "bowl" hearth a bit like a giant tobacco pipe. Air was blown into the furnace via the square duct: The photo below shows the filter presses at Carbis. These brought clay slurry pumped at pressure from the tanks into the bank of cast iron plates which were lined with filter cloths. Clay would then build up on the cloth eventually forming a giant 4ft square cake weighing about 200lbs. As you can see from the spatter on the roof, sometimes the cast iron plates would "give up" under pressure, which made a terrible mess. Here we see the Kubota KH-31 that was used at Prosper on the pan. It has it's own heavily reinforced travelling bridge, which it was able to move itself along on using the arm. This machine was used to break up and distribute fresh filter cakes across the pan, and also to remove dry cakes to the linhay. Lastly, we have the tram wagons on the other travelling bridge, which were used to carry the filter cakes from the press house to the desired spot on the pan. As you can see they were side-tipping. Early oil fired mechanical dryers built between 1939 to around the early 50s were all built as an extension onto the original coal fired dry, which itself was usually modified by the internal removal of the redundant "pan" and installation of conveyor belts to carry dried clay through it. ECC's first "big" modern conveyor fed linhay was built on Par harbour around 1951, and was a second hand derigible hangar from RAF Davidstow. The company installed a pair of large rotary peanut roasters inside, and set them up to dry china clay. After just a couple years the plant at Par proved a success, and so the company shifted from mechanizing old dryers to building entirely new plants. The vast majority of coal fired dryers were shut down during this period as they were replaced by huge new plants capable of orders of magnitude higher output. Here's a photo of the linhay in question at Par in 1951, former RAF hangar of truss construction, being assembled around the pair of peanut roasters: A closer photo of the peanut roasters sat on their giant concrete plinth:

It depended on the size of the dry, but a very simple calculation can be done. 1 short ton of coal will boil 10 tons of water. Clay to be dried was about 20% moisture, so for every 5 tons of wet clay 1 ton of that was water. Most coal fired drys were producing 2.5 tons per hour, so that's 1/20th of a ton of coal, or 100lbs an hour. That's a reasonable rate of shoveling considering the furnace had to be fired by the same men who shovelled dry clay off the pan. So your answer would be somewhere around 30 tons a month. After about 1950 ECC mostly trucked their coal from Par harbour to the dries, putting an end to coal by rail, except in cases of distant dries such as those around Bodmin Moor. They continued to receive coal by rail until they were updated to oil fired mechanical dryers.

Looks about right for one of the smaller stores. You may be interested to know the small one at Kernick, on which the scalescenes was based, was originally half the size, it was doubled in I think the mid 60s. There was also a really tiny linhay on the Goonbarrow branch which I think was only about 100 feet or so in length. It was fed by ECC's 1939 vintage Rockhill rotary dryer. Fun fact, during the 1978 coal strikes, Rockhill was prepped to dry peat from Bodmin Moor to fuel Drinnick power plant!

Looking at what you've got there, I think you could get more "frontage" if you built your kiln angled around the curve, and used the turnout to form a coal stub instead. Forgive the rather crude drawing, but this should roughly demonstrate what I mean:

The Parkside wagon represents the 1913 GWR wagon dia O13. It seems the last examples were withdrawn in the late 1950s as they were replaced in batches by the new BR wagons. Some sources I've read say that they were all vacuum fitted by 1939, but I have photos from later with no evidence of vacuum hoses. Entirely possible that some remained unfitted to the bitter end or that the information is simply inaccurate, unfortunately I've got no reference material to verify. The main detail differences between the old GWR vs newer BR are angled vs straight bufferbeam ends, spoke instead of disc wheels, different axleboxes, and I believe subtly different brake gear although don't quote me on that as I'm far from being an expert. The hybar style tented sheets were added to this latter set of BR wagons in 1974 as a refresh in lieu of total replacement, and supposedly done to make the sheets easier to handle. So the ratio kit can make either the flat sheeted type introduced mid to late 50s or the hooded type '74-'87, while the Parkside kit would cap out at 1959.

The downside with the Parkside wagons are that they're simply too early, including the axleboxes which are a different type (albeit subtly) to the later ones. The ratio kit is the most accurate apart from the axleboxes, which are fairly easily removed using a sharp knife, and can then be replaced using Dart Castings RCH axlebox, a bargain at £4.20 for a pack of 12. https://www.dartcastings.co.uk/mjt/2241A.php Dart also make a 12 pack of BR SKF roller bearings, which in addition to a wee strip of corrugated styrene at each end, is useful for converting RTR BR 5 plank opens to clayliners. https://www.dartcastings.co.uk/mjt/2256A.php

The Hewas Inn has always been a hidden gem in the area known for it's good food. Many clay area locals use it as the go-to "fancy restaurant". Seeing the photos of your developing layout has given me the serious itch to draft some suggestions for fictional clay works. That back left corner in particular has good potential.

Many thanks to all who replied, this mystery has now been solved thanks to Ray Hill, who worked for the Goonvean and Rostowrack China Clay Co Ltd for most of his working life. This photo shows Ray at the helm of a Lansing Bagnall forklift within the linhay of the Trelavour dryer in 1971.

I took another look at the photo and realised that the linhay under construction is actually the Buell dryer linhay, and the rotary linhay appears complete. I had initially confused it with the construction of the rotary and it's linhays, which date to 1956. The Buell installation at Blackpool was of a pattern also constructed at Rocks, Drinnick, and Marsh Mills, all in the early 60s, which corresponds to Peter's date. Here's a photo from 1962, the following year. Taken from Blackpool refinery on Burngullow common, looking down toward Blackpool. The rotary building is the one with steam rising on the left, containing 4 rotary units. The Buell building is the one with the steam rising on the right, containing 2 Buell units. The long row of linhays consisted of 13 bays and an attritor mill, with a total capacity of 20,800 tonnes. As you can see the silos have yet to be constructed: This photo is the one I was thinking of, taken in 1956 during the construction of the rotary: Blackpool was quite a complex. At it's height it was producing almost a third of the industry output, with the other two big producers being Rocks and Par. Here's a look inside the rotary building, looking at No.3 and No.4 rotaries. No.1 and 2 were behind the cameraman. These big drums were about 7 feet in diameter and roughly 50 feet in length. The upside down "U" shaped things hanging on the frame over the conveyor belts at the bottom of the photo are horseshoe permanent magnets to catch stray metal. The filter press decks are on the left and right, these filtered the liquid slurry into a solid cake which could be dried. Each rotary unit had an output of approx 10 tons per hour, for a combined peak output of 40tph, enough to fill the entire linhay in 21 days.

I don't know if having a year would help at this point, Trevor, but the photo with the bus at Burngullow shows Blackpool dryers under construction, which occurred in 1956.

Pentewan, Par, and Crinnis beaches all have a considerable amount of mining and streaming waste on them. Partly clay waste, partly mining. And yes it is rather sharp. The river that emerges from the cave in the cliff at Crinnis/Carlyon Bay is the same river that flows through Sandy Hill, and was used as a discharge by the mines of that area, and then later the clay industry. A lesser known fact of the mid Cornwall mining area, is that before Pentewan, Par, and Charlestown were used for clay export, they shipped tin and copper concentrate, and the local rivers ran red. Much of the early silting problems had little to do with the fledgling clay industry and more to do with the huge metal mines of the area, such as Polgooth, Great Crinnis, and Fowey Consols.

The silting of Par came about 100 years before Treffry's harbour. The village itself was originally confined to what we now consider West Par, and grew up around Par Consols mine. After the construction of the harbour it spread out on to the flats of what was being called Par Green, which then was just fields, the earliest development being a single row of south facing cottages on the north side of the road, one of which later becoming The Welcome Home Inn. Par station stood isolated to the north, and originally served mainly the much larger community of Tywardreath to which it was closer. You are correct that Blazey Bridge on the road to Tywardreath Highway was the original crossing point. This is an extremely old road, medieval or older. The small settlement of Pontsmill was once a fairly busy 16th century port, capable of receiving 80 ton vessels as late as 1720, by which time the river had been reduced from two navigable forks to one by streaming and mining activity in the valley.

I remember in my youth when they were still white! There were a couple, but "THE" white river, aka the River Vinnick, flowed down from Gover and Trenance, through St Austell valley and out to Pentewan. The other originated from the great underground canal of Great Carclaze/Baal china clay works, down through Sandy Hill, emerging onto the beach of Carlyon Bay, which is partly why there's a beach there. Did you know the entire village of Par sits on the silt from tin streaming waste which used to flow down the Luxulyan valley? That's why it's so flat. At one point it was a wide bay estuary which was navigable as far as Pontsmill. Sorry, I'm going off topic with Cornish pub quiz trivia. Trevor I'm looking at your photos and thinking that garage/MOT station or whatever it is looks a bit close to that embankment to my eyes. Just a suggestion, but if it were me I'd move it forward a touch so that you can have an earth bank rather than one of those awful retaining walls that too many modellers resort to (in my humble opinion).

Was he buying you pints of strong cider, by any chance? That's how he always got me hammered. Always thought he was going to the bar to get himself one, then he'd come back with two and put one on my beermat... felt rude to just leave it. Next thing you know you're on your way to the toilets, run your hand through your hair and realise you can no longer feel your scalp!!

Operations at Nanpean Wharf were always awkward. There was a loop just south of where the line down to the Wharf diverged from the branch. This loop was used for Dubbers and West Of England sidings, and could provide a run around for the wharf, but trains were limited in length by the wharf forming a considerable chunk of the headshunt. If wagons were present at the wharf when a train had to run down to the lower lines, those wagons would have to be removed to the branch before the train could proceed. This was further compounded by the loop at some point being truncated into a siding removing it's functionality, meaning that the lower level sidings were only accessible as a propelled reversal from the wharf. Trains leaving the lower level sidings would have to run the locomotive around the wagons and propel the train up to the wharf in order for the locomotive to be on the correct end of the train if it was travelling back toward Burngullow. More often than not though, train movements at Drinnick were scheduled to take place as part of other workings up the branch, meaning the train could be propelled back up the incline toward the branch to rejoin part of a longer train as it worked toward Treviscoe or Parkandillack.

I know this building, it's Treviscoe rotary. The large structure in front is the linhay, the smaller structure with the almost white roof in behind it is the dryer. Notice how although the panel gaps are visible on the structure in the foreground, they are invisible on the newer roof in the background. The photo is a low resolution zoom of a drone image, but I strongly suspect the reason the panel lines are so visible is due to moss growing in the gaps. The same thing happened to Parkandillack New Buell: You can see how on some parts of the roof the panel lines are nearly invisible, while in other areas they're highlighted by moss and weather staining. Tom Johnson has proven very well that the effect can be created entirely with weathering on his HO scale Logansport and Indiana Northern layout. This building is a completely unmodified Walthers Cornerstone kit (I know because I own the same kit) and the only physical panel lines it has are the horizontal. The illusion of individual panels and vertical laps was created by Tom's process of weathering each panel individually before going on to the next, and highlighting the joints with a carefully applied pinwash.

If you're interested I have a track plan for a layout based on the low level lines. It's slightly condensed to retain the linhay on the right and rail overbridge on the left as scenic breaks without taking up too much space, and having the added operational interest of the power plant coal chute. Designed to fit on an 8ft x 2ft plywood, using Peco EM gauge Bullhead as a good standard for realistic curves and turnout lengths. I also have a "close enough" mockup of the building in sketchup.

Agreed, it really isn't visible at distance. Far more noticeable is colour variation of sheets and gaps, where differing materials and weather occlusion create natural highlights.

The method for corrugated roofing that I've used with great success is to cover the entire roof in styrene sheet to provide a gluing surface, then cut the corrugated sheet into strips of the desired size and glue them onto the styrene sheet. Then above each strip lay a thin strip of styrene to bolster the bottom end of the next strip so as to create a visible lap. This example is a HO scale grain elevator and feed mill complex that I've had on the back burner for a while: Although I've never tried it, I believe it would be quite possible to use this method to create the lap between individual sheets. I've never bothered, choosing instead to create the effect using weathering.

There's always the option of doing half relief. If you like when the time comes to figure out this aspect I could mock up a couple of 3D models for your consideration. I'd just need a basic idea of the trackplan and the available footprint for structures.

Also probably worth mentioning that I have modelled several prototype and fictional linhays, drys, and other related structures in Google Sketchup Make 2017, which is an easy to use 3D software available for free download online. If you are interested in these models for research purposes, I can email the model files upon request.

The old coal fired pan kilns have the major disadvantage of being long, averaging around 250' to 300'. I only ever encountered one rail served prototype of "layout size" at Burngullow West, which may be of particular interest given it's location. It's actually still extant in remarkably good condition complete with piles of clay, despite about 50 years of abandonment. It shared the rather grand square chimney with the neighbouring kiln. I conducted a survey of the building before I left the UK and have attached scale drawings. Also attached and possibly of interest, is Burngullow West's bag store, a standalone building which apparently received clay via blondin from the dry opposite. This structure is visible on the right hand side in most photos taken from the bridge next to Burngullow station, looking toward the St Dennis branch where it diverges from the mainline.