A Ffestiniog Experiment: part 2 Merddin Emrys gets a makeover

[David B]

Ask me an easier one JB! I set off with the best of intentions. EoM has a larger stablemate which also needs flexible steam pipes:



The original burners in the Accucraft NGG16s weren’t quite as reliable as they might have been, and had a tendency to overheat residual steam oil in the smokebox, which then dripped onto the flexible steam pipes below and, er, burned through them. Result - clouds of unexpected steam and a failed loco. How do I know? I replaced mine with new heat resistant PTFE pipes designed for 3D printers:



The PTFE works a treat in the Garratt (although the ultimate solution was to change the gas jets and use stainless steel mesh to create a fully effective pair of burners). So I thought this would be ideal solution for EoM. Until I tried to connect the PTFE to the stainless steel superheater tube at one end and the cylinder block at the other. There was enough flex, but I couldn’t find a way to secure the cylinder end reliably. So I admitted defeat and ordered a pair of flexible steam pipes with pre fitted connectors from Roundhouse. I know, I know, I could have said that at the beginning, but I did try to come up with my own solution……

 

[michael mott]

Nice work David Fitting all that control gear in such a tight space is not easy. a simple question what is the tightest radius curve that the loco will negotiate?
Michael

 

[David B]

Thanks Michael - my tightest curves are 5 foot radius, which it navigates with ease, but I doubt it would get round anything much tighter, because there isn’t a huge amount of room between the flanges and the base of the boiler.



You wouldn’t want to get your fingers caught in there…..it would be easy to put an extra washer or two on top of the bogies, or (less easily) turn down the flanges to scale proportions. Ride height has always mattered disproportionately to me. When I was scratch-building 7mm English Electric diesels years ago, it was alway important to me that the bodies should have that characteristic heavy low-slung look with just the right amount of air gap above the bogies - nothing worse than that teetering ballet dancer look that you get with some of the older commercial 4mm Class 37s. And it was the same with this Double Fairlie - it needs to sit solidly, ride solidly and look, er, solid.

 

[Scale7JB]

Ask me an easier one JB! I set off with the best of intentions. EoM has a larger stablemate which also needs flexible steam pipes:

View attachment 153605

The original burners in the Accucraft NGG16s weren’t quite as reliable as they might have been, and had a tendency to overheat residual steam oil in the smokebox, which then dripped onto the flexible steam pipes below and, er, burned through them. Result - clouds of unexpected steam and a failed loco. How do I know? I replaced mine with new heat resistant PTFE pipes designed for 3D printers:

View attachment 153606

The PTFE works a treat in the Garratt (although the ultimate solution was to change the gas jets and use stainless steel mesh to create a fully effective pair of burners). So I thought this would be ideal solution for EoM. Until I tried to connect the PTFE to the stainless steel superheater tube at one end and the cylinder block at the other. There was enough flex, but I couldn’t find a way to secure the cylinder end reliably. So I admitted defeat and ordered a pair of flexible steam pipes with pre fitted connectors from Roundhouse. I know, I know, I could have said that at the beginning, but I did try to come up with my own solution……

Thanks, I had assumed it would be a hinged type metal pipe due to heat, rubber/ptfe had never occurred to me, but I guess the saturated steam in 16mm/ft is far cooler than that of a 2-300lb superheated full size version.

JB.

 

[Chris Veitch]

Thanks, I had assumed it would be a hinged type metal pipe due to heat, rubber/ptfe had never occurred to me, but I guess the saturated steam in 16mm/ft is far cooler than that of a 2-300lb superheated full size version.

JB.

The modern prototypes actually use a flexible braided pipe as part of the live steam circuit, described in some detail by the CME in Fairlie Locomotives of North Wales.

 

[David B]

Time for some plumbing - plus another new challenge for me. I’m used to tinkering with the weight distribution of other models in order to have enough adhesive weight on the driving wheels and enough downforce for pony truck/bogie springs, but I’ve never had to calculate the weight on each side of a loco before, let alone as carefully as I had to do it for this engine. It’s not quite the full Listowel & Ballybunion, but it became clear very quickly that the weight needed to be very accurately and evenly distributed in order to avoid The Earl looking the worse for wear after a good night out in Blaenau (if such a thing is possible?). I wanted to have both gas tanks on the same side (under removable coal loads), which meant putting the electronics and batteries for the radio control in the tanks on the opposite side, plus some carefully measured extra steel ballast to even things up.

Here are the lubricators in place, apparently doing some strange synchronised Snowdonian dance with their pipe ‘arms’:



At this stage I haven’t cut out the dropped footplate below the lubricators.

And next is a photo showing one of the flexible steam pipes mentioned earlier - the steam circuit is relatively long for a 16mm loco, with the steam being taken from the boiler via the turret at the rear end before passing through the regulator, then into the superheater down the length of the boiler flue to the smokebox, then back under the boiler to the firebox end via the flexible pipe (the white tube in the photo), then round the rear drivers and finally forwards again under the driving axles to the cylinder block. It’s not a huge distance, but it’s enough to make the the loco slower to respond to regulator changes than more conventional miniature steamers.



And lastly, in a bit of a jump forward, here is the main running board primed and painted, with cut outs for the dropped cab footplate, plus a steel cradle for the electronics (apologies for the very roughly dressed ends of the mild steel - I was getting impatient…..) and the carefully calculated steel balance weight at the other end. The holes on the opposite side show where the gas tanks will be fitted.



In the background are the smokeboxes, prepared, primed and painted in high temperature barbecue paint. I have added the new hinge strapping and I’m in the process of painting the details.

 

[Dog Star]

What you write about achieving balance prompts the request for you to explain, with pictures, how the boiler/smokebox unit is supported on the bogies along with how bogie swing is controlled / centred.

Nice photos, thank you.

regards, Graham

 

[David B]

Good question Graham - I wasn’t taking a full blow-by-blow set of photos during construction (just taking enough to keep my brother and my dad updated on progress), but I’ll do my best to explain. Here is one of the power bogies:


I took the photo to show the exhaust arrangements, but it also shows where the bogie pivot is located - there is a small brass screw head sticking up in the middle of a roughly semicircular horizontal brass washer just in front of the rear wheels. The washer is sitting on the top of the bogie bolster. It’s that size because I needed as wide a washer as possible to stabilise the body (I tried using smaller diameter washers, but the body wobbled all over the place) and it’s that shape because I had to remove the front quadrants which were snagging on the inside motion just in front of the pivot, as you can see in the photo.

The bogie is attached to a brass stretcher which is bolted underneath the running plate. You can see the freshly painted stretchers in the photo in my previous post, but here is a close up:



They need a raised centre section in order to accommodate the wide brass washer while still keeping the ride height low, and the central mounting screw needs to be deeply countersunk because the boiler is virtually resting on top of the stretcher.

The bogie swing is limited in a very unscientific way at the rear by the flexible steam pipe between the rear driving wheels and at the front by the exhaust pipe, which needs to fit between the valve gear, then bend forward and up through the smokebox and finally into the very narrow base of the tapered chimney, while also being able to swivel to accommodate the movement of the bogie. More on that shortly.

I hope that helps.

 

[David B]

And so to the next instalment…..while the paint was drying on the running board and smokeboxes, I did some test fitting of the reversing servos (Graham - you can just see one of the embarrassingly small and completely useless washers I first tried on the left hand mounting point, per my post above):



As I’m sure Chris V will be able to confirm, the real reverser on The Earl needed a very firm hand - the first time I tried to notch her up, I felt as if my arm was about to be wrenched from its socket. It felt so out of place, with the loco riding so very smoothly, but the minute I unlatched the lever, it was as if some angry troll sitting below the footplate was pulling and pushing and shaking and vibrating all of the reciprocating parts of the valve gear as hard as he could. A small servo making a smooth whirring sound is a bit of a letdown in comparison.

To the right of the photo you can just see the two black rectangles of the gas tanks lying on the workbench, which I bolted to aluminium angle to keep them aligned and parallel when mounted on the footplate.

The next task was to prime and spray some mid Brunswick green on the boiler wrappers and the cylinders, and then apply some red lining. I used Pressfix transfers because I’d already proven their heat-resistance elsewhere.

I also wanted to make sure my model had a voice. The real Earl of Merioneth sounded magnificent when working hard - if you never had the chance to experience it, search YouTube for F&WHR: Farewell to the Earl of Merioneth - 7th and 8th April 2018 and watch the first 25 seconds of the video with the sound turned up. Now I was never going to be able to replicate that with my gas-fired model, but I could make sure that the exhaust beats were properly audible. I used a pair of Summerlands Chuffers which I modified and silver soldered to some carefully shaped copper tubes. They slot in place over the top of the stubby exhaust pipes fitted by Roundhouse to the bogies. The chuffers are then free to rotate as the bogies moves. If you compare the photo in the post above (with the organ pipe of the chuffer facing to the left of the bogie) with the one below, you’ll see how the chuffer can pivot as the bogie turns:



Now nobody is ever going to say that the sound from a chuffer can replicate the beautiful noise of a Double Fairlie lifting 12 bogies up to Dduallt, but fitting them at least means that I can clearly hear the different exhaust beats of the twin bogies. It also means that the loco and my rolling stock are not spattered with a thin spray of steam oil. Most 16mm modellers seem to like a high gloss finish, where a light coating of oil can be polished in. My background in the smaller scales means I prefer satin and matt finishes, which don’t respond so well to regular doses of steam oil, so the way that the chuffers redirect the oil back down to be burned in the smokebox is a helpful side benefit.

Oh yes - admission time. I didn’t get the bends in the exhaust pipework quite right to begin with, so the first few runs of The Earl produced the odd side effect of a periscope slowly rising from the top of the chimney, caused by the chuffer catching slightly each time the bogie moved, and edging upwards as if on a ratchet until it disengaged completely, the sound disappeared and the chuffer (unhelpful) fell down unsupported into the smokebox. D’oh!

 

[Dog Star]

Graham - you can just see one of the embarrassingly small and completely useless washers I first tried on the left hand mounting point, per my post above.

David, your answer is why I asked the question about support of the boiler unit. Thank you.

 

[Chris Veitch]

As I’m sure Chris V will be able to confirm, the real reverser on The Earl needed a very firm hand - the first time I tried to notch her up, I felt as if my arm was about to be wrenched from its socket.

Ha ha - regrettably not. My experience is limited to a little trainee firing, quite a lot of cleaning (hence the bruises and burns) and a bit more tinkering with various restoration projects in Boston Lodge. I have however had a go with Linda, which has a similar tendency which I think is common to slide valve locos with lever (as opposed to screw) reversers, but other more knowledgable chaps may know better.

My more common role on the footplate of a double Fairlie is that of closing the draincocks for the driver when getting a lift back to the works (because as a passenger you're in his way), but you can just about do that with your little finger.

 

[oldravendale]

Had a go with Linda?........

 

[simond]

A most obliging lass.

In my teens, I fired her & her sister as Warren Shepherd or Phil ? drove. Several very happy summer holidays.

 

[oldravendale]

......fired her and her sister...... What? At the same time?

Nurse!

(With due apologies to all of a nervous disposition)

 

[David B]

Festive greetings to all WTers - and thank you for your continued interest in this slightly random thread. And hark, what is that sound? Could it be the seasonal ring of jingle bells heralding the arrival of Santa’s sleigh in 16mm?



Er, no…..what you can hear is me grouching about the unavailability of Mick Davies’s invisible solder. Don’t worry, it was all cleaned up after the photo was taken.

I’d started thinking about how to build the superstructure of the loco and decided on four main subsections. I would build the side tanks for each end as a single unit which would fit over the boiler and incorporate the lower cab sides; a removable upper cab section for easy access to the lubricators and water top up valves; and Santa’s sleigh beneath the cab and including the unusual flared ash pans which almost touch the railhead and which which help to give The Earl his (her?) heavy, low slung look.

So first up it was time to reassemble the painted components. With the shaped ends to the steel cradle for the r/c electronics and some FR green paint, it’s finally starting to look a bit more like The Square:



Time for some serious scratchbuilding…..

 

[D6356]

Wow is all I can say. Way back when I was on the train that took the old Earl to Glan y Pwll using the new Earl. Worked on the line since 1979 and was sad to see the Earl slowly softened its bulk said 1970s utility engine built when every penny counted- its size was to give enough oil space for two round trips and take up as much water as possible. Famously a model made out of fag packets sat in the Den at Boston Lodge for many years. The biggest fail I had on it was up the line when that reverser lever broke - well the lug for one end shaft so we ended up with a double push me! stopping on the official sixpence on tank curve. Needless to say Evan used the one controllable end to get the train to Dduallt. This thread is a great read and I look forward to more as time allows and like the builder look forward to the day that EoM in its 1970s guise reappears.

 

[Tim Watson]

Fascinating model. Reminds me of Dick Relph’s live steam models.
Tim

 

[Chris Veitch]

Worked on the line since 1979 and was sad to see the Earl slowly softened its bulk said 1970s utility engine built when every penny counted- its size was to give enough oil space for two round trips and take up as much water as possible.

It is - to date - the only loco I've helped to fill up with fire buckets, although this was due to the failure of the Tan-y-bwlch water tank valve rather than a lack of capacity! It's interesting to see how many FR volunteers come out of the woodwork on what I always think of as a GWR forum...

 

[David B]

Thank you to everyone who has shared FR reminiscences - it’s a pleasure to read them. The crew that gave me my day out on The Earl (Aled and Richard - great guys) told me that EoM was a favourite with many FR crews because it always did whatever was asked of it with a minimum of fuss - I’m not sure that the reverser lever breaking would be too popular though! I remember standing on the platform at Tan-y-Bwlch and hearing the most extraordinary racket from a loco hammering up through the woods - it turned out to be Prince with its regulator jammed wide open - the crew weren’t able to close it, so were driving on the reverser.

Time for a quick word on some of the resources I drew upon for the model. I used the drawings in the David Payling book mentioned in my first post, scaled up to 16mm:1 foot. I was also very lucky to find this website 2017-06 UK 5. FfFFF - EoM which is packed full of detailed photographs taken by a Dutch enthusiast. I don’t know what possessed him to take so many close ups of The Square, but I am very grateful to him for doing so. Even so, I still had to search long and hard to locate photos on the web showing the top of the loco and the steam manifolds tucked in between the domes and the cab.

So using photocopies glued to 1mm brass sheet using photo mount adhesive, I started to cut out some parts:



Apologies for the scratches (from dressing the cut edges) - I took the photo before I removed them with fine wet and dry. Here is the part offered up to the loco for the first time:



I’ve also installed some of the electrics for the radio control in the side tank - there’s a rechargeable 4 x AA battery pack, a charging jack, a receiver, some over-long servo leads and a servo reverser (to make sure that the different ends of the loco work together, rather than against each other).

Here’s a view from the other side showing how I’m starting to build out the panels under the cab that enclose the firebox. It also shows the gas tanks mounted in place. The blue plastic boxes in the cab area are the regulator servos, which were a complete nightmare to install and fine-tune. More on them later…..



And lastly for today, the first of the side tanks cut out and held in place temporarily, plus the main parts of the outward-flared ash pans are now in place under the cab, giving the low-slung heavy look that I like so much:

 

[David B]

Fascinating model. Reminds me of Dick Relph’s live steam models.
Tim

Great to see Dick Relph mentioned. His models were a real inspiration to me. I love the way that he was a true innovator as well as an excellent modeller - there wasn’t nearly enough about his work in the modelling press, but I read and re-read every article I could find. I’ve just gone back to my copy of the mid-70s part work The History of Model and Miniature Railways, which I avidly collected as a 9 year old, to refresh my memory of his article in Part 33. It’s well worth re-reading - there was something groundbreaking about the idea of combining traditional powered rails with live steam to create remote electric control of an indoor live steamer. Very clever stuff.