MikeOxon

8 hours ago, stevel said:

Who's driving wheels did you use for these, I would like to build some singles but not sure where i can get the right wheels.

For my 'Queen' model, I used 'Alan Gibson' wheels. 

As @Annie pointed out, you can use 'Lord of the Isles' wheels for the larger singles.  I used a couple of pairs of these, bought from 'Peter's Spares', for my original 'Rob Roy' model, for which they had the advantage of having the correct 24 spokes.  I did have to turn down the flanges.

For my 'Sir Daniel', I have 3D-printed my own wheel centres, with the correct number of spokes.  The Broad Gauge Society plans to make a range of metal wheel rims available, to suit various large-wheeled engines.

1 hour ago, Miss Prism said:

I think what probably did for the 2-2-2s was their high middle axle weight (and the hammer blow).

The photo demonstrates how, with all that extra 'top hamper' the Dean engine really needs the front extension to restore some sense of balance.

2 hours ago, JimC said:

Here's my sketches of an original Dean and an original Sir Daniel side by side.

Thank you Jim, for showing that comparison - a good example of a picture being worth a thousand words 🙂

11 hours ago, ChrisN said:

 

You will say they are vastly different.

Where do I begin, Chris ...🙂  Dean was faced with the problem of rapidly increasing train loads - he needed more steam, which meant larger fireboxes, large domes and bigger, heavier cylinders.  It all got too much for the 2-2-2 chassis that had served since Stephenson's time.  His engines were looking heavy and lumpish after Armstrong's light touch!  Dean was saved by adding a front bogie that restored more elegant proportions but by then the days of the 'single' engine were numbered.

Dean - over size domes etc.

40 minutes ago, Annie said:

I must confess to liking the elegant simplicity of Joseph Armstrong's engines.

I agree, their proportions are aesthetically pleasing.

3 hours ago, Miss Prism said:

The one on the right is a real sweetie.

 

as opposed to a right bear

No.111 was, of course, also allocated to 'The Great Bear'.  The two '111's were brought together for a joint photo at Swindon, presumably when the 2nd version was new:

4 hours ago, Mikkel said:

I assume the print bed must be easy to clean? (I'm speaking with nil experience, as you know).

 

I've been using my old Geetech printer, which has an unheated bed to which I apply a layer of blue painters tape as the working surface.  As that gets worn, I simply strip it off and replace it.  The Prusa has a detachable build-plate that can easily be removed and washed when necessary, so no problem either way. 

I decided to use the Geetech until the current head fails, since I am totally familiar with it, but it will 'expire' before long, because the proprietary heads are no longer available.  It is possible to convert the machine to take an 'Ender' head but other parts are wearing out too. I had a lot of teething troubles with it but it has become a good workhorse and I still like its 'domesticated' appearance,

I need to bite the bullet and get used to the Prusa but there 's new firmware for it just been released, so I shall install that first.

As a modeller, I like to have a few key dimensions - especially wheelbase and, hopefully, visible boiler length and diameter.  The last can be problematic as it rises the question of cladding thickness, so actual diameter is probably the best thing to quote and then leave it up to a modeller's judgement. 

On the whole, I think that, in a survey of this type, the initial build is the most important thing.  Trying to track every detail of re-building has to be done on an individual engine basis, as boilers etc. got swapped around all over the place!  (e.g. 'Sir Daniel' No. 386 carried a boiler which had previously been on No. 166 (157class))

I suggest you pull out the general features of each 'Designer's period' in an introduction before starting on the individual classes.

It'll get more difficult when you get to the Armstrongs and the division between Swindon and Wolverhampton styles!

14 hours ago, ChrisN said:

It would have been a 2-2-2 that pulled the 10:02 to Birkenhead in early 1895

I suppose I have come full circle in my modelling - my first scratch built model was a 2-2-2 of GWR 'Queen' class.  I chose it because it was simple to build, with no coupling rods and critical alignments.

41 minutes ago, David Bigcheeseplant said:

Have you tried Fusion 360 which is free to use, you can get colours correct and get things to look more real.

You achieve some beautiful renderings with 'Fusion 360', Dave.  Although I use this software myself, I have still not mastered the rendering to such a splendid degree.  Do you have any tips for the rest of us to achieve such results?

Mike

It was some time before I discovered Part 3 of the RCTS survey of GWR engines. Incidentally, it's great to see that these Parts are now available on-line.  

It's a large Part but, while there are some fascinating 'odd-ball' engines, I'm not sure it contributes much to the line of GWR loco development.  The most significant part of the history is probably what experiences Joseph Armstrong brought with him to Wolverhampton from the Shrewsbury and Chester works at Saltney.  Apart from that, I think the rest could be omitted as peripheral.  

A glance at the contents pages of Ahrons 'The British Steam Railway Locomotive 1825-1925' might give some food for thought. 

He mixes several different methods of classification - starting by time periods, within which he traces various lines of development.  He punctuates this progression by occasional chapters on 'performance', which includes the effects of various technical developments.  There are also some chapters on very specific types of locomotive.  In the GWR context, the special needs of the Welsh valleys comes to mind.

Mike

1 hour ago, isambird said:

looked like it came from the Locomotive Magazine.

Yes, I tracked it down to The Locomotive Magazine Vol. IV, No 40, April 1899 - the accompanying text states:
"Unfortunately but very little appears now to be known concerning the old broad gauge locomotives of the North Devon. Our first illustration shows the "Star", a 7-ft. single engine reputed to have been built by Bury, though certainly not possessing the usual "Bury" characteristics .This engine had a six wheeled tender, the brake gear being operated by toothed wheels at the back attached to a rod running along inside the coping. The " Mole," " Exe," " Tite " and " Barum " were similar engines ."

A nice find - I might be tempted to model one myself.

Mike

Now found a drawing in Mike Sharman's selection of locomotive drawings by Oakwood Press.

Mike

"Today's blog post introduces a new locomotive, definitely not well-known as others but still as beautiful"  

I suspect it's little known because it never belonged to the GWR, so is missing from many books.

It seems that it was first used on the Bristol and Gloucester Railway, where it was named 'Cheltenham' and was built by Stothert & Slaughter to designs by Bury. 

Where did you find the illustration you used as the basis for your model?  I couldn't find one on the web.

Mike

Many thanks - I see you mention Roblox in the intro. to your blog.  I had wondered about those coupling blocks! 

So, do you do all the model design within that software?  I assume that it's fairly limited, in comparison with dedicated CAD software.

One comparison I would like to have made was with Stephenson's 'Rocket' but I couldn't find my old Airfix/Dapol 4mm-scale model. 

I have, however, found .stl files on the 'Printables' website, for a 'Rocket' model by Václav Krmela.  I imported his files into 'Fusion 360', scaled them to 4mm/ft, and placed his model alongside the Trevithick model for the following comparison:

(Rocket model shown without tender)

An important step in the 'locomotive line of development'.

Mike

6 hours ago, Mikkel said:

You should tease the youngsters and pretend to have printed this in one piece

If only it were!  As it stands, it wouldn't survive for 30 seconds in the grandchildren's hands.

1 hour ago, Northroader said:

Real genius.

I'm currently reading Anthony Burton's 'Richard Trevithick - Giant of Steam'.  James Watt had tried to put a stranglehold on steam engine development though the use of far-reaching Patents.  Trevithick's use of 'strong steam' was the break-through that moved things on.  He created the steam engine as we know it.  That was indeed real genius

Good to know this is still running.  Those etches look very nice but you will have fun assembling all those small parts!  I find that, when doing a repetitive job, I seem to 'program' myself into a steady routine, so that it becomes almost automatic to put them together - good luck and I hope the show goes well!

Mike

Thank you @ChrisN.  I must give credit to the Czech modeller who placed his .stl files on the 'Printables' website for the overall design of the model. 

I was, frankly, amazed by how well it printed at only about 20% of the original size.  With a little more attention to detail, mainly in the design of the cross-head, I think mine could have been a 'rolling' model.  It has served my purpose, though, by enabling me to place the model alongside early GWR engines.

15 minutes ago, Annie said:

In 4mm scale it's so darn tiny.

indeed it is - and it almost drove me to distraction at times.  I dropped the chimney just after assembling it to the curved pipe at the base and then could not find it, even with a finger-tip search of the floor!  The glue had not hardened and it had stuck itself firmly to the side of my sock!!! 

Stick to the virtual world where such things don't happen 🙂

1 hour ago, Jeremy Cumberland said:

Wow! Four hours and no water put in the boiler.

The boiler was pretty large (6' x 4' 3" dia) and not full of tubes either, which may be relevant factors.

I agree, Jeremy, that there are many puzzles remaining concerning exactly what happened at Penydarren.  I also agree that all the other drawings I have seen show the flywheel crankpin aligned with  one of the spokes but there could have been a separate crank as you suggest, since that is the arrangement on the other side of the drive shaft.

One account claims that the rails through the tunnel were moved and that this led to an argument over the prize being awarded.  It might mean that the rails were offset to give maximum height over the flywheel.  It is probable that the chimney was removed or lowered, as the boiler would retain sufficient steam for the passage through the tunnel.  There's a passage in a letter to Mr Giddy that says: "It is above nine miles , which we performed in four hours and five minutes. We had to cut down some trees and remove some large rocks out of the road. The engine, while working, went nearly five miles per hour ; no water was put into the boiler from the time we started until we arrived at our journey's end ".  That was a very long time to travel 9 miles and allows for plenty of stoppages to deal with various obstacles.

Regarding your books 'wish list', the biography by Francis Trevithick can be downloaded free from the Internet Archive website.

Mike