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Recreating LYN
Progress log page 2

This is page 2 of the design and detailing blog for the recreation of the 1898 Baldwin narrow gauge locomotive known as LYN. The work on this project started at the begining of 2011 and to see the blog of the work during 2011 and 2012 please go to
page one.
For the current Status of the Detail Design and Drafting (28/04/2014) please go here

GoTo the latest entry

Modelling progress up to 6th February 2013

The chassis assembly has now been updated by adding the motion, valve gear, the saddle and the cylinders.

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This is the latest jpg of the loco chassis.

Modelling progress up to 25th February 2013

The manufacturing drawings for the valve gear and all its bits are mostly completed and waiting for checking. Ian has completed the design of the reverser and I have now modelled it up and added it to the engine main assembly. Ian and I are having a design review tomorrow to iron our a few things that the modelling has thrown up. Ian has started designing the axle boxes and I am looking forward to getting them modelled. I have just today received some pictures of the work in progress at Alan Keef. I especially like the picture of the valve turning and am quite jealous of the chap doing this work.
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Machining the valve body.
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The finished valve end caps.
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The finished cylinder end caps + other parts.
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The regulator gland.

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The reverser assembly.
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The reverser in the cab.

Modelling progress up to 7th March 2013

I am busy completing the detail design of the reverser and I am getting on with the detailing of the manufacturing drawings. I have also updated the valve mechanism with the addition of a lubrication system for the dieblock. This takes a feed from the oil distribution unit and drips it into a trough feeding a pipe that directs the drips of oil onto the top of the dieblock.

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Dieblock Oiling.
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Complete model of the boiler.
Click on the picture for a photo of the real boiler.

Modelling progress up to 9th April 2013

Ian Gaylor has finished the axlebox design layout and passed it to me the . I have finished modelling the main components and the chassis assembly has the axle boxes and the hornblocks fitted. As the areas are finished the frame is being updated to the latest geometry. We have a major design review meeting next week and I am aiming to have all the areas that we have designed fully modelled so that we can get any tricky areas reviewed.

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frame with the axle box.
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Lyn's frames.
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Exploded view of the axle box showing the bearing.
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Section through the right side driving axle.
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Section showing the high grip wheel rim profile based on the work of Engineer Livio Dante Porta. click on the picture for a more detailed description of how it works

Modelling progress up to 10th April 2013

The main axles are now assembled and all the parts modelled. I have started the detail drawings for these. the final shape for the flycranks is sorted and the model now reflects the latest shape.
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trailing axle assembly.
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leading axle assembly.
Here are a few more pictures of completed parts. There is now a page with the latest information on the whole project go here to read it
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piston and valve parts.
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piston and valve parts.

Modelling progress up to 24th May 2013

Not much new to report. I am updating the watertank models and drawings. These were some of the first parts modelled back in march 2011 and needed final updated to take account of all the parts now completed and fitted to the main modeled assembly. There are a total of 3864 components assembled together to make the engine so far. This number includes all the fastenings, pins, circlips, boiler stays, and more than 700 unique components that will be manufactured.

Modelling progress up to 24th June 2013

The drawings for the water tanks have been completed and issued for manufacture.
Andy Bennett has completed the hydraulic testing of the boiler and is about to start the superheater manufacture. He has asked me to see if I can simplify the manufacturing by making the header as a casting. I have looked into this and it is much too expensive mainly due to the pattern cost but, whilst I was looking at this, I realised that the existing design of a single component made from parts with a lot of welding could be re-designed as 2 chambers that clamp together when assembled to the boiler and that this makes it possible to make the design much simplier and the welding much easier to do.
Another area of the superheater that was causing difficulty was the actual tubes that go into the boiler flue tubes. The company, Willingale Tubes, had found that the original design had too many bends close together and to solve this they were proposing to weld together short pre-bent lengths. This would make the job much too expensive and I could see that it would be possible to achieve the same result with just single bend. This sort of design exercise is made much easier because of the use of 3D CAD modelling tools. Here are a few pictures showing the old and new design:-
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Original Header Design.
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New design Header Front Chamber after welding.
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CNC Machined main body.
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New design Header Front Chamber after final machining.
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Exploded view showing the 2 chamber design.
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New Design for Superheater.
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superheater fitted to boiler showing simplified tube bending.

Manufacturing progress up to 26th June 2013

Probably not the latest information but here are some more pictures of finished parts from Alan Keef

cylinder end plates
Finished Cylinder End Covers.
cylinder end plates
Cylinder End Cover Port Machining.
Finished Cowcatchers Covers.
cylinder end plates
Machining the Piston Rod Bearing Blocks.

Modelling progress up to 6th July 2013

Further improvements have been made to the superheater design. This time the clamping of the ball ends to the header has been simplified by using a separate collar (the purple things in the picture below) to pull each ball into its seat and a simple block bridge to apply the force. This has solved a potential conflict between the centres of the header and the centres of the clamp and also made the welding of the ball end to the tube easier.
ball clamp end plates
detail of the clamping of the superheater to the header.
ball clamp section
section through the tube mounting Machining.

Modelling progress up to 18th July 2013

I have now almost finished the redesign of the reverser. The original design incorporated a toothed belt to both transmit the drive from the handwheel to the leadscrew and to create the 2:1 gearing to enable the use of a leadscrew that wouldn't back-drive even under the most extreeme loads that the valve mechanism could apply (flat out with a complete failure of lubrication). Ian has now finished a redesign and I have modelled it up and it looks good. The drive is now carried by a pair of bevel gears giving the 2:1 ratio and the indicator is on the top of the unit in a more traditional manner.
ball clamp end plates
Reverser driver side view.
Reverser mechanism.

Reverser in cab, driver view.

Modelling progress up to 25th August 2013

No New pictures this month ( I have updated the picture above to show the gauge frames and protectors). The reverser design is now approved and I am starting the detail drawings ready for manufacture. I have provided DXF (a 2D data file used for cutting flat sheets) files for the bunker to the potential manufacturer and STEP (a 3D data file used to provide the accurate geometry to the CNC program) files to the super heater chamber manufacturer. I am expecting the checked valve gear drawings back from Ian shortly and will get them updated and issued soon. I have also been supporting the Boilermaker as he fits the smokebox and the crinolines. The gauge frames have been added to the boiler backhead

September 2013 More finished components

I am working on the design of the cylinders to see if I can design out some of the manufacturing cost and trying not to sacrifice any significant performance in the process. It is really encouraging to see some of the major components coming together.
Here is the saddle at Alan Keefs. This view is on the rear of the saddle and shows the exhaust steam connections to drive the GPS firing system and above that the connection for the steam that creates the draught when the engine is stationary. The 2 white rags on the top are pushed into the steam connections to the cylinders (we don't want any bugs in the system).
There are a lot more pictures on the 762 club's site go to Lynformation or click on the picture to be portkeyed to the page in a flash!

October 2013

The boiler has now been to Woody Bay for its first visit and looks superb. The major part of the welding on the superheater headers is completed. The 2 chambers have been tack welded back to back while the front and back plates are welded in. This ensures that the headers don't distort when the welding is done. The units will be stress relieved before the tack welds are ground off and so should remain flat. The parts used to clamp the superheater tubes to the headers are finished. The pictures show the parts but for the correct assembly please refer to the pictures of the superheater model above.
Also finished is the front end of the drypipe that connects the front of the boiler to the superheater header

Simplification of the valve cylinder machining
ball clamp end plates
Original port design.
ball clamp end plates
Simplified port design.
The original design required that the ports at the front and back (the exhaust ports) aligned perfectly with the ports in the liner. This change should significantly reduce the cost of the machining. A less obvious change has been to increase the number of the inlet ports (the ones in the centre) from 15 to 16. This change means that the liner rotational alignment is no longer as critical as, with 15 equi-spaced slots matching 16 equi-spaced exhaust ports, there was only 1 solution to the alignment whereas now there are 16 and the precision demanded is much reduced. This change should not have any impact on the engine performance.

October 22nd 2013

I have put the detailing of the reverser on the back burner for a while as there are some more pressing tasks needing attention. It has been decided that the steam dome needs to be split and achieving this entails quite a lot of changes in addition to the obvious dome split. The mounting for the regulator valve has had to be lowered to place it below the split line. The linkage for the regulator has had to be shortened. The trumpet on the top of the valve has been extended to compensate for the lowering of the valve.
One major change has been to the supporting of the regulator shaft. Andy Bennett wondered if it might be possible to support it from the drypipe elbow and I have now produced a design that achieves this.

steam dome original
Original steam dome design.
split dome
Split dome design.
split dome
Split dome and internals.

November 9th 2013

The valve gear and the motion are now checked and released for manufacture. The superheater headers are welded up and, having been stress relieved, are being machined and the superheater tubes are being welded. The boiler steam dome has been split and the flanges are welded on. No pictures yet but I will post any that I can prise out of Andy Bennett.

connection rod
Connecting Rod Assembly Drawing.
coupling rod
Coupling Rod Assembly Drawing.
slide bar
Slidebar Assembly Drawing.
Crosshead Assembly Drawing.

November 28th 2013

The driving wheel and axle assemblies and the reverser assembly are now detailed and issued for checking.
I have finished the work to suck some of the cost out of the cylinder assemblies and we have a meeting mid December with the likely contractor for the manufacture.

front wheel set
Front wheel set assembly drawing.
rear wheel set
Rear wheel set assembly drawing.
slide bar
Axle box assembly drawing.
Reverser assembly drawing.

December 22nd 2013

We (Ian Gaylor, John Scott,Peter Best and Mike Nelson) visited FW Frost Ltd who will be manufacturing the cylinders for LYN. This is one of the trickier assemblies and we have a lot of confidence that Frosts will do an excellent job. They have done similar locomotive work before. We are expecting the cylinder assemblies to be delivered in June 2014.
John Scott is the ICP (Independent Competent Person) for the LYN project and ensures that all the eyes are dotted and the tees crossed.
The boiler continues to move forward. The steam dome has been split, the drypipe and the J pipe are now fitted and the regulator lever and shaft assembly have been test fitted. The headers for the superheater are now finished and ready to fit.
I have the Vacuum Gauge, the whistle and the Drivers brake unit to model and add to the assembly.
I think that we (the design team) will be finished the design and the detail drawings by the end of March 2014 (subject to the usual caveats!). and from then the only thing holding back the build will be the funding.
Peter Best visited Andy Bennett last week and took a few pictures.
boiler 1
Boiler with the dome split and the crinolines added.
boiler 2
Boiler backhead and regulator lever.
boiler 3
Steam dome (on the top is a temporary lifting loop).
boiler 4
Drypipe before fitting.
boiler 4
Superheater headers.
vacuum gauge
Vacuum Gauge, a gift to LYN from Roger and Sara Davies.
Whistle. Castings for this were donated by The Puffing Billy Railway in Australia.

January 25th 2014

The axle assemblies and the axlebox assembly have been checked and the manufacturing drawings completed and issued for manufacture. The trailing axle has been a tricky assembly as it also carries the valve eccentrics and it is vital that these are assembled correctly to ensure the valve events are as close to perfect as possible.
The regulator and all its connections has been successfully assembled by Andy Bennett and it looks good. It has certainly justified the splitting of the steam dome as I doubt that we could have assembled it through the top flange. Andy has sent me a couple of pictures of the regulator all assembled.
The superheater headers have been successfully fitted and the superheater tubes are now being made. I have designed a welding jig in co-operation with Andy Bennett and the main part has been detailed and issued. I have a couple of secondary jigs to make to help locate the tubes when the return castings are welded on.
boiler 1
regulator assy.
regulator detail
Close up of the regulator in the steam dome.
boiler 3
Boiler backhead and regulator lever.

March 5th 2014

The blast stand and the spark arrestor are ready to me made and the bunker is nearing completion. The simulated riveting looks convincing.
A bit slow this month sorry about that.
bunker 1
Bunker side view.
bunker 3
Bunker back view.
bunker 4
Bunker riveting detail.

March 15th 2014

First pictures of the patterns for the cylinder covers. Really beautiful work by Brian Lloyd. It is really encouraging that these skills are still available.
bunker 1
Cylinder Cover Pattern during construction.
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Cylinder Cover Pattern finished.

March 31th 2014
I have started the modelling of the pony trucks and am currently grappling with the design of the front truck. we have to make some changes to cope with the tighter curves of the Welsh Highland.
Here are some more pictures of actual parts. The chimney is nearly finished although we still have to add the injector exhaust internal piping. The driving wheels look finished to me and the pony truck wheels are cast ready to machine/
bunker 1
Chimney assembly.
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Machined driving wheels.
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Truck wheel castings.

Here are a couple of pictures Peter Best took on a recent visit to Bennett Boilers. More will appear in the next edition of Lynformation.
bunker 1
First view of the superheater and its tubes fitted to the boiler.
bunker 1
Boiler now sporting water gauges.
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Safety valve.

April 18th 2014
The water tanks are well advanced and here are a few pictures of the work in progress. The lads in the photos are Roger Beal and the apprentice is Aiden Brackenbury. It is very heartening to see the skills being passed on.
The bunker is now finished and looks great. I need to check with Peter if it is OK to post the pictures.
bunker 1
Water Tank Team.
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Water Tank.
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Water Tank.
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Fettling the tank.

April 19th 2014
The bunker is now finished and looks great. Here are a couple of pictures.
Bunker rear view.
bunker 1
Bunker back view.

May 10th 2014
I have been working on the design of the fire door. I originally did the design early in 2011 but always felt that the hinge and closing mechanism would need a redesign. click here to see original design. Ian found a picture of a more robust handle and latch mechanism and I have developed this into a robust and (hopefully) reliable mechanism. The handle is lifted to disengage the latch and the door can be swung open until the latch re-engages locking the door open. I have aimed to give a good clear opening to make firing easy.
The drawings for this assembly are complete and have been issued for quotation.

Fire Door Closed.
bunker 1
Fire Door Open.

May 12th 2014
The building of the engine is progressing an accelerating pace. The wheels have been pressed onto the axles. The water tanks are finished and painted in undercoat. The axle boxes have been machined. Here are some pictures.

Water tanks finished and undercoated.
bunker 1
The team responsible. The chap in the middle is Michael Guppy who has made such a great job possible.

The machine used to press on the wheels. Quite different from what I expected.
bunker 1
Patrick and Phil checking the job.
The axle press in action.
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Axle boxes machined and waiting to be assembled onto the axles.

May 27th 2014
Not much new at present. I have started the process of getting the frame drawings underway. we still lack all the information that we will need to complete the drawings but I have started the assembly drawing that should enable the issue for quotation.
frame drg
Frame assembly drawing (not finished).
click on drawing to download the 3 sheet pdf.

June 30th 2014
Brian Lloyd has finished the patterns for the firebars. Here are a couple of pictures.
The finished woodwork before painting.
bunker 1
The finished pattern ready for casting.

July 2nd 2014
I have modelled the main spring mounting assembly ready to detail. The 2 spring hangers shown (items 10 & 11) connect to the frame and the other end of the spring will have longer versions that connect to the long lever linked to the springs on the front and rear pony trucks.
frame drg
spring mounting assembly drawing (not finished).
click on drawing to download the drawing pdf.

July 14nd 2014
I have spent some 15 hours today modelling up 3 items that we won't need to manufacture as we already have them but I need the models so that when the locations and fitments are created I can be sure of a clash free fit. The items are the whistle, the Drivers Steam Brake (at least that is what I think it is) and the Vacuum Gauge. The Vacuum Gauge eas interesting. It was very easy to model but I hadn't used the decal (transfers to us Brits) tools in SolidWorks. As you can see it went well. I just photo'd the gauge face, roughly cut it out in Paint Shop Pro, applied it and added a bezel to cover up the rough cutting out.
vacuum gauge
Modelled Vacuum Gauge.
steam brake
Modelled Drivers Steam Brake.
Modelled Whistle.

July 24nd 2014
Had a short design review meeting with Ian yesterday and sorted out a number of issues with the axle assemblies. Nothing too important but it is good to keep on top of these things. We also looked at how we can strengthen the loco's frames as this design is known to be very weak and easily damaged if inexpertly handled after a derailment or during any work requiring the wheel sets to be removed. Ian has produced a possible addition to the frame that will significantly reduce the risks of damage and not be visible from the outside. I have continued to model up some of the bought in parts.
I have nearly finished the ashpan update and have issued the detail drawings for checking. I still have to have a review meeting with Ian to check that I have done everything but we should be ready to issue for manufacture fairly soon.
Steam Brake Displacement Lubricator
Steam Brake Displacement Lubricator.
Modelled Gauge frame (bottom left shown).

August 28nd 2014
The frame strengthening exercise is now finished and I am updating the frame model to show the added strengthing assembly. Below is a picture showing the added stiffening in red. This extra material will not be visible as it is tucked up between the water tanks and the boiler but should bring the strength of the chassis closer to that of a plate frame. you can also see the semi circular recesses we have added to the front of the frame to accomodate the extra movement of the front pony truck when the engine is running on the Welsh Highland railway.
Stiffened frame
Stiffened Frame Assembly.

September 08th 2014
The cylinders are under construction at Frosts of Norwich. Here are the first pictures of some of the parts. The main plates have been water jet cut and the cylinders and liners machined (the liners just proof turned to ensure the material is flaw free). The cylinder end flanges have been CNC machined to give the steam passages.
cylinder end flanges showing the CNC machining
cylinder end flanges showing the CNC machining.
cylinders machined
cylinders machined ready for assembly.
Steam Transfer Port Profiles.
Steam Chest end Plates
Steam Chest end Plates.
Main Cylinder and Steam Chest
Main Cylinder and Steam Chest.
Cylinder Liners Proof Machined
Cylinder Liners Proof Machined.
Exhaust Guide Parts
Exhaust Guide Parts.

September 09th 2014
The blast stand has been beautifully welded together at Alan Keefs. Here are some pictures. The pipe up the side of the unit is to allow steam to be fed to the lempor to continue the draught even when the loco is stationary.
Blast Stand all welded up.
blast stand 2
Blast stand part.
Blast stand part
Blast stand part.
Blast stand part
Blast stand part.

October 5th 2014
I am well on with the front pony truck model. Here is the first picture.
Pony Truck Model
Front Pony Truck.

October 15th 2014
We have had a design review of the recent design elements including the pony trucks and the frame. The project is going well and it looks like we are on track to have a running engine by the end of next year. The cylinder fabrication is running behind schedule and delivery of these major items isn't now expected until February 2015.
The frame design is now very advanced and we hope to start manufacture early next year. The design of the front pony truck design is very close to complete and detailing should start later this month. The rear pony truck is a much more difficult design problem mainly due to the lack of space but Ian has come up with a very clever linkage that looks to solve the problem with this assembly. I will do an item on this once the design is complete.

Cranks and crank pins.
Main wheel Sets.
Blast stand part
Fire Bars ready to use.
Valve conrods part assembled.
Machine the valve cylinder.

October 16th 2014
The 2 valve cylinders are now machined and look great. The steam cylinders are on the milling machine for the ports to be machined.

Valve Cylinder machined.
Steam Cylinder set up for port milling.

October 21st 2014
Those of you who read the Lynformation will have seen the Gresham and Craven number 6 Gradable steam brake but if you haven't here is a picture of it. I have it to create a CAD model so that it can be mounted on the main model assembly and we can thus be sure that the mountings are accurate. Also just received are the loco suspension springs.

Gradable steam brake
Gradable steam brake.
Valve chest top cover casting
Valve chest top cover casting.

October 25th 2014
Here are some pictures of the suspension springs being made

Spring Materials.
Heating the spring.
End forming first bend.
Finishing the ends.
Finished end of spring leaf.
Spraying the springs.

October 26th 2014
Robert Frost has sent me some pictures of the progress on the manufacture of the cylinder/valve assemblies. So far only parts but they look very good.

The 2 machined cylinder bodies.
Steam cylinder port detail.
The completed valve cylinders.
Finished steam chests.
Steam chest detail.
Liner Guide and instrumentation boss.

November 2nd 2014
The machining of the cylinders continues and here are some pictures of the steam transfer ports. The lugs around the edge are to facilitate the mounting on the milling machine and will be removed later in the manufacturing process. Also shown are the valve conrods.

Valve conrod fabrication.
Steam transfer ports initial machining.
Steam transfer ports stage 2 machining.

November 3rd 2014
More photos of parts for LYN. These are the slide bars and are being machined by Whiteland Engineering the workmanship looks very good.

Crosshead bottom slide bar Machining.
Crosshead bottom slide bars ready for heat treatment.
Crosshead Top Slide Bar Machining.
Crosshead Top Slide Bar Roughing out.
Crosshead Top Slide Bar Machining.

November 7th 2014
More photos of parts for LYN. These are the crosshead blanks waterjet cut ready for machining.

Crosshead blank
Crosshead waterjet blank ready for machining.

November 8th 2014
More photos of progress on the prefabrication of the cylinders being built by Frosts of Norwich. This assembly is very demanding as the considerable amount of welding involved makes maintaining the accuracy very demanding.

Steam Chest Fabrication.
Steam Chest Fabrication.
Steam Transfer Ports ready for Assembly.
Cylinder & Steam Chest.
Cylinder & Steam Chest.
Cylinder & Steam Chest.
Cylinder & Steam Chest.
Cylinder & Steam Chest.
Cylinder with End Flange.

November 17th 2014
A couple more photos of progress on the prefabrication of the cylinders being built by Frosts of Norwich. This assembly is very demanding as the considerable amount of welding involved makes maintaining the accuracy very demanding.

Steam transfer port welded in position.
Steam transfer port showing the internal corner radius fillet added.

November 21st 2014
A three more photos of progress on the prefabrication of the cylinders being built by Frosts of Norwich. Lots more welding done and the end flanges are fitted.


December 4th 2014
The wheel sets have been completed by Alan Keef. An important milestone and Ian and I are pushing on with the pony trucks so that we can have the frame built in the new year.


December 12th 2014
I have now issued the leading pony truck drawings for checking and started the modelling of the trailing pony truck. Here is a picture of the leading pony truck. Click on the picture to download a PDF of the assembly drawing.

Also just received are some new pictures from Frosts of Norwich. They are getting on well with the cylinders.
And some more pictures from Frosts of Norwich received on the 17th December. They are still getting on well with the cylinders.

January 16th 2015
The couplings for LYN are being made by Ffestiniog Railway Company. Here are some pictures of ones that they have already made for the L&B carriages and are identical to the ones for LYN.
January 30th 2015
The cylinder fabrications are now finished and they are about to go for stress relieving (vital to take the stresses generated by the welding out of the assemblies)prior to starting the machining. The assemblies are bolted together so that the mounting flanges will stay as flat as possible during the stress relieving process that involves heating the assemblies until all the stresses are relaxed.

This blog continues on page 3

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Useful links

762 Club Homepage
Lynton & Barnstaple Railway Homepage
Ian Gaylors's Homepage
Bennett Boilers Ltd Homepage
Alan Keef's Homepage

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