Great Southern Railway (Fictitious) - Signalling the changes...

[Skinnylinny]

That crane looks rather lovely, Steve! The resin I'm using at the moment is the Anycubic green. Once cured it's pretty rigid, so what I've been doing with the last few wagons as an experiment is printing the underframe as one piece, curing, placing in hot water to soften the underframe just enough to pop the wheels in, then squeezing everything tight so that it cools straight, and finally another quick blast in the curing station. Then it's time for paint. 

Another vehicle is just about complete - this one was done in a day to the point seen here, and just needs lamp irons, a gas tank (already added since the video was taken) and vacuum pipes (which I will probably print separately and glue on).
 

This is definitely a luggage van and not a full brake or guard's van - there is no facility within the vehicle for applying the handbrake. The gas-lit versions were often used for newspaper traffic. The brake gear as modelled is somewhat simplified, with only the most visible bits being modelled (the rest needing various bits of bent wire to be formed around the axles once in place) and was an absolute pig, with the actuating rods coming from a central operating rod, then coming out diagonally through the brake shoe, and to a compensating rod outside the axleguard. I wouldn't fancy building that even at 1:1 scale!

[Steve Smith]

Thanks Linny,

 

Do like that van, and would run that sort of thing if anything like it had survived into 1950s East Dorset.

 

A bit of the printing process I can't get my head around is how it prints horizontally away from a support, and when we printed the crane wheels in 7mm using the supports that worked perfectly in 4mm it started off  with a few droopy delaminated layers at the outer edge of the safety guards before buckling down to print properly - so it's a distance thing but also depends on the machine as my supports were too far apart at 4mm to work in another 3D printer for the first production batch.

 

As for deformation - the resin crane weighs diddly squat, the chain not a lot more so when the pillar deformed in what was fairly weak sunlight I could see that an admittedly small unbalanced load on the slender pillar might cause this.  The big surprise that has potential implications for any of our 3D printed models is that the stout jib couldn't seem to hold its own weight plus whatever compressive force that light chain could impose on it.   My solution was to print voids and insert metal.   The translucent blue ABS like resin used was not as brittle as subsequent prints in grey, black or green.  It would be interesting to know if these more brittle resins are stiffer (since this is how these things normally work), and therefore behave more like the moulded plastics we are familiar with, but since that first crane, all test builds have been reinforced as a precaution.

 

Steve

[Nick C]

Is it just me or is there some seriously wierd perspective rendering in that video? It looked like the end furthest from the viewpoint was getting bigger!

 

The CAD looks great though!

[Skinnylinny]

Ah yes, my apologies - the "camera" was set for orthographic mode, not perspective!

[richbrummitt]

3 hours ago, Nick C said:

Is it just me or is there some seriously wierd perspective rendering in that video? It looked like the end furthest from the viewpoint was getting bigger!

That’s default 3D CAD views for you. I’ve got dumb to it after 10+ years in several similar software tools. I assume they all do it unless you turn the perspective setting (where available)

[Skinnylinny]

Not much to update today I'm afraid, as I've been busy with actual paying work (!) but I did get a parcel through the post with four large sheets of drawings by Mike King of various SECR birdcage carriages.

For my £10, I got drawings for: 

D423 50'1" Corridor Brake Compo
D145 45' 3-compt Brake 3rd
D147 50'1" 5-compt Brake 3rd
D310 51'1" 6-compt Compo
D422 46' 6-compt Brake Compo
D236 38' 5-compt lav 2nd (same drawing for D32 3rd)
D46 46' 8-compt 3rd
D48 48' 7-compt 3rd
D152 50'1" 5-compt Brake 3rd
D154 50'1" 2-compt Brake 3rd
D244 50'1" Saloon Brake 2nd (same drawing gives D168 saloon brake 3rd)
D292 44' 6-compt compo (same drawing gives D486 1st)
D293 44' 6-compt compo (same drawing gives D487 1st)
D294 44' 5 1/2 compt compo (same drawing for D44 3rd and D237 2nd)
D319 62'6" 10-compt compo (same drawing for D50 3rd)
D304 50'1" 6-compt compo
D306 51'1" Saloon Compo
D488 45' 6-compt 1st
D426 50'1" 4-compt slip brake compo (1st/3rd)
D490 50'1" Saloon 1st
D548 45' 5-compt brake 1st
D613 38' 1st invalid saloon (as rebuilt 1907/8)
D621 50'1" 3rd saloon

They're all in a pale purple ink, which makes me think Roneo/Banda printing, rather than photocopying, but there are certainly some interesting carriages in there, albeit all in Southern condition. That said, a 46' brake composite (2x1st, 2x2nd and 2x3rd compartments) would be perfect for a Linton boat train connection, if combined with a 4-wheel Grande Vitesse luggage van (the carriage having no real luggage compartment of its own), while being short enough to require an entire extra train (as would probably be the case with two bogies and a luggage van).

Edited January 31, 2021 by Skinnylinny

[Lacathedrale]

Very interesting @Skinnylinny - I had spoken to Mr. King about some ex-SECR EMU drawings. I don't suppose it would be possible to show an excerpt to see what we get for our money?

 

Many thanks!

[Nick C]

On 31/01/2021 at 13:44, Lacathedrale said:

Very interesting @Skinnylinny - I had spoken to Mr. King about some ex-SECR EMU drawings. I don't suppose it would be possible to show an excerpt to see what we get for our money?

 

Many thanks!

Most of the books covering SR rolling stock have Mike's drawings in them, albeit reduced to fit the page sizes.

[Skinnylinny]

Moving on from the LSWR luggage van, I've set myself a rather harder challenge this time. I'm trying to design a locomotive such that it will be easy to motorise, easy to fit weight into, and easy to paint and line, meaning several components that will come apart and be put together once painted. I figured that a 4-coupled loco would be about as easy to motorise as they come (I didn't fancy a single!) and adding a tender for extra pickups probably wouldn't go amiss. Then, of course, something that's been preserved would allow access to plenty of photographs online for reference...



There's a long way still to go, and a lot of work to be done, but things are definitely taking shape. 

[Compound2632]

1 hour ago, Skinnylinny said:

easy to paint and line

 

... so they chose a Brighton passenger engine.

Edited February 2, 2021 by Compound2632

[Skinnylinny]

Ah, well, you see...

https://www.ebay.co.uk/itm/LBSC-B1-waterslide-full-lining-decal-set-4mm-Croydon-Gladstone-choose-names/143926872435

(Oh, by the way, I go by "they", not "he")

[Compound2632]

33 minutes ago, Skinnylinny said:

(Oh, by the way, I go by "they", not "he")

 

Sorry, I knew that. Corrected in post.

[Edwardian]

2 hours ago, Skinnylinny said:

Moving on from the LSWR luggage van, I've set myself a rather harder challenge this time. I'm trying to design a locomotive such that it will be easy to motorise, easy to fit weight into, and easy to paint and line, meaning several components that will come apart and be put together once painted. I figured that a 4-coupled loco would be about as easy to motorise as they come (I didn't fancy a single!) and adding a tender for extra pickups probably wouldn't go amiss. Then, of course, something that's been preserved would allow access to plenty of photographs online for reference...



There's a long way still to go, and a lot of work to be done, but things are definitely taking shape. 

 

Yes please!

[Skinnylinny]

Oh, and just for those who complain that LBSC locos might be difficult to line... 



Yes, I know the boiler bands and cab front need doing, but doesn't she look pretty!

[Nick C]

2 hours ago, Skinnylinny said:

Oh, and just for those who complain that LBSC locos might be difficult to line... 



Yes, I know the boiler bands and cab front need doing, but doesn't she look pretty!

Give it another decade and we'll probably have 3D printers that do colour, then it's easy...

[richbrummitt]

18 hours ago, Nick C said:

Give it another decade and we'll probably have 3D printers that do colour, then it's easy...

 

You mean like the Z Corp machines that have been around for a decade already: Example Z-Corp review

[Regularity]

Possibly a bit smaller, cheaper and lighter, though - 300kg! Ouch.

[Skinnylinny]

Another fortnight, another update. The B1 has been playing second fiddle to some other work, but does seem to be coming along nicely. I've had to make a few allowances for overscale wheel treads on 00 wheels - the brake rodding is a little further apart than I would ideally have liked! That being said, Mr Stroudley had some interesting ideas on locomotive brakes, it would appear - I've never seen anything quite like these before. Steam brakes, I assume, with a cylinder attached to each of the inner two brake hangers, pulling on rodding to pull the two opposing brake shoes on each wheel together. Then a screw adjuster at the outer ends. Most unusual, and the cylinders were fed by small curvy pipes (not yet added) from a steam main running behind the coupled wheels.



A lot of not-very-visible work has happened on the model, with some representation of inside motion (well, slidebars, crossheads and Stephenson's link hangers!) between the frames, and some cab controls. I seem to be getting better with the Fusion renderer as well, meaning I can get some lovely shots of work as it stands!

 

Still a long, long way to go yet, but I am at least thankful for the use of flush-head rivets!

[Mikkel]

That's beautiful Linny. I've gone all weak at the knees now.

[Skinnylinny]

Thank you, Mikkel - it might not be a physical model yet, and I doubt that my painting skill will do it justice, but it is being designed in many pieces to make it as easy as possible to access bits for painting and applying transfers. I don't want to fall into the trap of a 3D printed model with an enclosed cab which is impossible to paint!

Case in point: The cab:



Fusion allows me to colour-highlight separate components, which gives an idea of the number of separately-fitted parts designed into the model so far: 

 

[ianmaccormac]

Those OO gauge splashers in the cab look very unobtrusive, nice! Is there a way to taper the thickness of the roof at the rear so it looks thinner? Keep on going although the animation was pushing it to extremes! Cheers Ian

[Skinnylinny]

Indeed - I've been struggling with the cab roof, trying to hollow it out. I actually re-drew the cab roof today, and this time it hollowed out perfectly. I'm still not sure about the shape, it seems to be very tricky to draw!

The splashers seemed to be the least obtrusive way to fit 00 wheels - at first I tried making the side boxes wider but they ended up covering far too much of the backhead, and made fitting the controls in very awkward. 


As for the animation of which Ian speaks, I may have been playing around with a concept which probably won't make it into the finished model, but was lots of fun to create and animate:



The throw on the inside cranks of the B1s was quite large, so while the crossheads and slidebars are only slightly visible between the boiler and running plate, they're actually visible below the frames from the side!

[sem34090]

Just a thought, but given you've animated it could it not also be used for train sim purposes?

[Annie]

3 hours ago, sem34090 said:

Just a thought, but given you've animated it could it not also be used for train sim purposes?

From what Linny said though an awful lot of polys would have to be banished first.

[Skinnylinny]

As Annie says, it's very polygon-heavy, once exported in a vaguely-useful format.

Also, while SketchUp works on a polygon level while designing (which can be a pain for 3D printing because you can end up with infinitely-thin walls), Fusion models as solids defined by geometric shapes - a circle in Fusion is genuinely a mathematically-defined circle, and a cylinder is solid rather than just being a sort of wrapper. This makes life much easier for designing for physical models, but would be somewhat of a nightmare for a simulation.

I've also designed this with the intention of it being physically assemble-able from parts in real life, so there are clearance gaps and hollow parts all over the place, and parts designed with minimum thicknesses based on what the printer will do, rather than what would be accurate to scale, and it's also designed for chunky 00-gauge wheels which means a fair few compromises all over the place.

Finally, while it appears animated above, what I've actually done is create what Fusion calls a "motion study", which allows me to define (in the software) links and joints between the components (sliders for the crossheads, rotational joints for the wheels, etc) and see how they interact when any one joint is "driven" or moved. Unfortunately those joints wouldn't be preserved when exporting to a Train-Simulator-style file, so that animation work would all have to be done again!

Edited February 20, 2021 by Skinnylinny