How I constructed a Southwold Railway 6 wheeled Cleminson open wagon using PETG filament

I have always been fascinated by the Southwold Railway - its quirkiness and individuality as one of very few three foot narrow gauge railways in England. Their continued use of Cleminson six wheeled rolling stock is also another source of interest for me and so, when I got a 3D printer and developed skills in making my own drawings and designs, it seemed inevitable that I would produce my own 6-wheeled stock. Here's how I got on.

For this build, I also decided to experiment with using PETG filament rather than my more usual PLA. My conclusions as to how they compare are outlined in the conclusion.

 The wagon was first drawn as a kit of parts using a marvellous free online package called TinkerCAD.

The TinkerCAD design environment was developed for children to use and consequently its learning curve is quite shallow, unlike a number of other 3D drawing packages. Whilst it is not as powerful as these other programs, it is remarkable how fairly complex drawings can be made with a series of simple tools.

 For more detailed information on how to use TinkerCAD see How I drew a Southwold open wagon with TinkerCAD

Once all the parts needed had been drawn, exported, sliced and 3D printed, I set to work putting them together. The first task was to join the two parts of the wagon floor using the bridging piece - which also acts as the support for the sliding centre truck.

The bridging section was first glued to one of the floor halves ......

..... and then glued to the other, making sure the two sections of floor were properly aligned and square.

NOTE: For this build, I decided to use PETG rather than my usual PLA filament as an investigation into how they compared. See below for my conclusions.

You will notice that the pivots for the outer swivelling trucks differ slightly. The one on the left with the raised edge keeps the truck level as it pivots whilst the one on the right is flat and 1.5mm lower. This is to allow for some compensation of the right hand truck as it pivots.

Next, one of the end pieces was attached. To ensure it was perpendicular to the floor, a square was used while the solvent hardened.

The floor was positioned along the lowermost plank division line on the inside of the end.

This process was repeated for the other end piece.

The sides were then added.

To enable them to fit on the print-bed, these come as two sections - long .......

..... and a short.

They were glued together when they were joined to the floor - the division between the two sections coinciding with the joint between the opening doors.

I have also produced two variants on the design the match those found on the originals. One variant has no centre straps on the doors, .....

.... whilst the other variant has the coal merchant's name, MOY, in slightly raised lettering.

The second side was then glued on and the body left to harden off. 

NOTE: For PETG, I have to use a plastic solvent (I use Plastic Weld) which takes a couple of hours to harden whereas for PLA, the thick superglue sets within a couple of minutes.

To hide the joint between the two parts of the wagon sides on the solebar, a couple of filler pieces were glued on; .......

..... one on each side.

 I next turned my attention to the three trucks. The W-irons were glued to the cross-members.

NOTE: Before glueing on the W-irons, it may be necessary to to open out the holes for the axles to 3.5mm with a drill. This will depend on how cleanly your printer produces the parts.

One of the outer trucks then had two 1.5mm strips glued along its centre line to give it a very simple (but effective) form of compensation when mounted on the flat pivot.

At this stage, I test-fitted the Bachmann 21.5mm diameter wheelsets to ensure they ran smoothly in the bearing holes.

NOTE: I don't generally use brass bushes as bearings in the holes. Maybe my wagons don't get sufficient usage, but I haven't experienced excessive wear or binding over the years.

The trucks were left overnight for the solvent to harden before moving on to the next stage.

The centre truck brackets were cleaned up (PETG tends to produce a lot of strands and whiskers as it prints) .......

.... as were the holes into which they will be inserted.

Two brackets were then glued into place .....

..... and the centre truck positioned between them.

The other two brackets were then glued on.

NOTE: Since taking these photos, I have redesigned the brackets with larger flanges to more reliably hold the truck in place.

The outer trucks were then attached to their respective mounts (the compensated truck on the flat mount) with self-tapping screws.

The trucks were then tested to ensure they slid and pivoted smoothly.

The wagon was then tested on the track.

It was then given a couple of coats of Halford's grey primer from a rattle can aerosol and then given some light weathering. Buffers and my own design of hook and loop couplings were added and the wagon entered service.

NOTE: These photos are of the centre strap-free variant

 

PETG v PLA - My conclusions

As mentioned above, I decided to explore the possibilities of using PETG for this build to see how it compares with my more usual PLA filament. Firstly, I had heard accounts from some fellow modellers that PLA has a tendency to warp when exposed to hot sunshine and secondly I was slightly anxious about the biodegradability of PLA when being used in an outdoor environment.

Here are my conclusions

• PETG prints at a higher temperature than PLA and so will probably be less susceptible to the effects of hot sunshine
• PETG is a lot more tacky and so sticks to the print bed without any problem. Following advice, I coated my glass print bed with Pritt adhesive - not to improve adhesion but actually to help with removal of the parts after printing. Unlike PLA, one coating of Pritt lasts ages.
• PETG tends to string more readily than PLA and so doesn't require as much cooling (which exacerbates stringing). I set my fan to 25% - some recommend not using cooling at all
• The print temperature is more critical for PETG than for PLA. Too hot and stringing increases, too cool and the layers don't adhere. I'm not sure I yet have the temperature perfected as a lot of the surface detail on the parts (eg bolt and rivet heads) is being lost. I may need to tweak the temperature to improve this.
• I struggled to find a solvent which worked with PETG. Superglue didn't work, Pipe Weld adhesive was unreliable for small parts. Eventually, I discovered Plastic Weld was OK - but inhaling its fumes need to be avoided. A disadvantage of using Plastic Weld is that it takes far longer to harden off than the superglue I use for PLA and so construction time is extended to days rather than hours.
  
• I haven't experienced any issues with painting PETG as yet - but my experience is limited to only a couple of models.

Overall, at this stage, I don't think any advantages of PETG outweigh those of PLA - at least in the climate of Northwest England. I doubt the sun's temperatures will be so excessive that printed parts will suffer unduly and reading further suggests that PLA biodegrades very slowly (40 years when buried in a landfill site). 

Once this reel of PETG has been exhausted, unless I have a major breakthrough with solving the problems of stringing and gluing, I will probably revert to PLA

Download

The files are available for download (in 15mm scale) from the GardenRails.org forum. The files are free to download but a log-in is required and voluntary contributions towards the upkeep of the forum are always welcome (our accounts are published on the forum).

• Download link - https://gardenrails.org/forum/viewtopic.php?f=55&t=14098

Note: There are three variants of the wagon available.

1. As shown above
2. As above but with MOY (the local coal merchant) on the sides
3. Similar to #1 but with additional strapping in the middle of each door

Progress Report 87

The Northwest of England seems to have suffered the worst of the country's winter weather since my last update. Cheshire was particularly badly affected by flooding and, although this didn't affect the Peckforton Light Railway directly the canal adjacent to where Beeston Market station would have been located was breached after Storm Christoph blew through the area. This is reminiscent of the Big Wind which affected the area when the railway would have been in existence. In addition, we have had more snowfall than we have had in previous years which was eventually appropriate for a partial running session.

On a personnel front, the Chairman /  Chief Operations Officer has celebrated a significant birthday which resulted in the acquisition of a secondhand Bachmann Lyn which has been on the wishlist for many years. The day after my birthday, it was converted to battery power and radio control.

Rolling Stock

Bachmann Lyn

Having been offered a secondhand Bachmann Lyn for a reasonable price, I was anxious to convert it to battery power and radio control to see it running on the railway. Despite the weather, she was given a test run together with the new Southwold Railway goods stock described in my previous Progress Report.

The Lyn is one of the earlier designs and so the motor block is suffering from the adverse effects of the poorer quality brittle plastic from which the clamshell casing is constructed. One of the lugs for the screws holding the body to the block had disintegrated as had one of the lugs for the outside frames and, more significantly, one of the lugs for the screws holding the clamshell together. 

Having now given it a test run on the tight curves on my railway alongside my rolling stock I have realised it is not really appropriate for the PLR in its present form. After searching about for a suitable prototypical loco to convert it into, I have settled on a hybrid of two Cork and Muskerry locos - an 0-4-4 side tank loco with outside frames.

 As you can see, I have decided to model this loco as a 3D print. This is a bit of an experiment, as I have not modelled anything quite so ambitious from scratch. I have found it a bit of a challenge to design the loco so that it can be broken down into parts suitable for printing on my 3D printer. I am reasonably optimistic that it will work - as they say, watch this space!

Southwold Cleminson Open

I am steadily working my way through the variations in designs of Southwold freight stock. The various versions of the three plank open have now been catered for and, in time, I will print out at least one of each variant.

I have now turned my attention to the Cleminson six wheeled open wagons. As with the four wheeled opens, there was a range of styles, each of which will eventually be catered for. In the meantime, I am working on redesigning the undercarriage using my experiences of working on the six wheeled coach as a guide.

Operations

Partial running session

For the past five years we have had very little snow, so to have three generous falls of snow this winter has been quite a treat. I managed to have a partial running session with two trains running around the continuous circuit - a passenger train running twice and a pickup goods running down and back up the line. Shunting was kept to a minimum as the sidings were Snowbound.

In addition, I was able to run a passenger train on the circuit on New Year's Eve while we had an al fresco barbecue.

The weather forecast for the next few days is particularly awful, so it's doubtful I will be able to get out into the garden for a while. But in the meantime, I seem to have a few projects to keep me occupied indoors.

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Progress Report 86

 Well, another year nearly over - and what a strange year it has been!

Quite a lot has happened this year on the railway - the most significant being the arrival of a 3D printer and the knock-on effects that has had on my model making. My printer arrived at about the same time as the Covid pandemic. I am pleased to say that not everything that came out of China this year has been bad news - for me certainly!

Since my last progress report, the most significant progress has been the production of a range of new goods rolling stock - all 3D printed. Having spent ages working on the swivelling six-wheel chassis for the Southwold Railway coach, I decided to make a good wagon to accompany it. And after making one goods wagon, why not make a second, and a third and so on. It's now my intention to draw and make every style of wagon and coach which ran on the Southwold Railway. As a long-time enthusiast of the Southwold (I am the 25th member of what was originally the Southwold Railway Society and is now the Southwold Railway Trust), I have followed and am following the the history and development of the railway with great interest. It seems fitting that, having constructed two Southwold locos, I should now construct rolling stock to accompany them.

All my drawings for the 3D printer were produced using TinkerCAD. I cannot praise this marvellous online drawing tool highly enough. Having tried alternatives, I eventually stumbled across TinkerCAD almost by accident. I took to it immediately. It is straightforward to use and has a very shallow, almost intuitive, learning curve. If you have a 3D printer and fancy making your own designs for it, I suggest you give it a try - see How I drew an open wagon in 3D with TinkerCAD.

Southwold Railway Coach

I've made some progress with the coach since my last progress report. I have now painted it and made some improvements to the 6-wheel chassis to help it negotiate the tight curves and the undulations on my railway.

It now handles most of the problematic track on my railway, but there are still some occasional derailments at two locations. I'm trying to decide whether to work further on the chassis or to try ironing out the hump and the dip in my track.

Southwold 4-plank open wagon

This was the second Southwold wagon I tackled after building the short wheelbase van (see How I drew, printed and assembled a Southold van). I made some changes to the chassis for this wagon which I hope are improvements on the van's chassis.

The

I decided to use this wagon as the basis for a blog post on developing drawing skills with TinkerCAD - see How I drew a wagon using TinkerCAD.

 

Southwold 3-plank open wagon

 This seemed the natural successor to the 4-plank wagon - and besides, I've always been fascinated by the curved ends of this type of wagon.

The chassis is almost identical to the 4-plank wagon, which made the drawing of this wagon a relatively straightforward affair.

Southwold two-plank open wagon

Of course, after the 3-plank wagon, it seemed only natural to draw and construct a 2-plank wagon. This will make a really useful addition to the stock on the Peckforton Light Railway as I've not previously had any two-plank wagons.

 

Flat wagon

I actually drew this before the open wagons, but didn't get around to printing it out. Before printing, I tweaked the design slightly. Now I've constructed it, I realise it's not quite accurate when compared with photos in various books on the Southwold. 

I will probably change the design before printing out my next version to more accurately reflect the design I've seen in the photos.

 

Long wheelbase van

Although I started drawing this van well before making any of the other wagons, I wasn't entirely happy with it. So, once I'd made the other wagons, I returned to the drawings of this wagon and made a series of amendments which resulted in the the wagon which is here presented.

 

 

I am presently working on drawings for the 6-wheel open wagons and then will explore the other variations on the basic wagon stock.

 

I might then tackle the later enclosed versions of the balcony coaches although, I must admit, I am not a fan of their design.

 

 

 Permanent Way

Well, considering the weather, there hasn't been a great deal of opportunity for running trains. Over the past week, we had snow which was initially very slushy and wet. This was followed by a hard frost which turned it into something resembling concrete. As a consequence, there has not really been much opportunity to run trains, apart from a couple of test trains to try out the various combinations of 6-wheel Cleminson chassis for the Southwold coach (see above).

A happy New Year to anyone who might take the trouble to read this update. Let us hope that 2021 is less stressful and more relaxing than 2020 - which I think will go down in history as one of out less than successful years - on all sorts of levels.....!!!

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