Harlequin

I think that current domestic 3D resin printers are more homogeneous than people think and that it would be possible to set some design parameters that cover a large number of common domestic devices, design for that target spec, state what the parameters are when distributing an STL and for it to give good results on printers that fall within those parameters. Orientation and supports require some expertise but they would be part of the STL - not something the customer would be expected to do. The customer would only have to slice the STL, using the default settings for his/her printer. Ordinary domestic printers can do great things, as @chuffinghell shows above. Some friends and I made the CAD for this yard crane which I printed on my 3 year old printer:

I can tell you one reason for the external panel but it's not a very good one - and I'm sure not the main reason... It allows the number plate to be mounted centrally without rivets or screws penetrating the tank walls - as above. When the external panel is removed the number plate always seems to get moved next to the cab where there's no water inside. (The actual tanks are a very odd shape and not as big as they look from the outside.)

Here's a Small Metro (or a Medium Metro, depending whose terminology you use) with the external panel evident by the array of studs rather than lines of rivet heads:

Many older locos are a pain to convert to DCC. So when push comes to shove you might end up replacing them with newer stock and then the Code100 restriction would become less relevant. Coaches and Wagons are easy to rewheel. 3% gradient could be a problem for steam locos and anything more than a few coaches. There's a layout and track planning subforum where this plan would get more feedback from people interested in the topic.

I hope it's OK to reproduce just this detail for research purposes: At lower right is a section through the tank. You can see the 1/8th in outer plate, which hangs down and gives that distinctive appearance of the tank overhanging the running plate of the Metros. Then inside that the 7/8th inch gap, then the 1/8th tank wall itself and then angle irons joining the tank outer wall to the baffle plates. In the centre of the photo is the larger scale detail labelled "Stud between tank and panel plate" showing how the outer plate is held 7/8ths away from the tank wall. Elsewhere the drawing shows the positions of those studs.

I suggested in one of the other threads that it would be possible to make a ready-supported print for a generic home resin printer that would work for most people. And further, that you could test that idea by giving such an STL away and collecting feedback. Have you followed that idea up?

It's in GWRJ number 4, if you have it. (Drawing 14503, Swindon, June 1898.) If not I'll try to take a usable photo of it.

Thanks! The following question might be more up your alley, Mikkel (and anyone) - it pertains to things out in the daylight. ☺️ The side tanks were initially double-skinned with an array of studs holding the outside panel away from the tank wall. This was possibly only done on the condensing engines but we've recently seen photos of 517s, in another thread, with double skinned tanks but they never had condensing equipment. The drawing of the Large Metro I have shows a double skinned tank and total width across both tanks of 8ft 4in. The offset from the outside of the tank to the outside of the panel is 1in. It seems that at some point it was decided that this double skin was no longer required and locos were built with the more familiar rows of rivets showing the internal structure of the tank. Do we know when this happened and under what circumstances? Were the outside panels simply removed from locos that had them, thus making the width over rivet-faced tanks 2 inches less?

Wonderful stuff! Thanks, Miss P. I’ll study this properly tomorrow but there’s one immediate breakthrough - the second long lever (green arrow) is, of course, for connecting to the vacuum cylinder.

@JimC @Miss Prism @Mikkel Do you know what the connection between the handbrake winder and the brake rigging should look like on the Metros? This is looking up under the bunker end of the loco. The handbrake winder handle in the cab turns a long shaft with a screw thread at the bottom which engages in the "tuning fork" part arrowed red. That pulls up the lever arrowed orange, turning the cross shaft arrowed pink and pulling on the brake rodding (yellow). The question is, what should the connection between the red-arrowed "tuning fork" and the orange-arrowed lever arm look like? Secondary question: The drawing I'm using shows another longer lever arm (arrowed green) also centred on the pink-arrowed cross shaft. I assume it is fixed to the cross shaft and my best guess is that a spring might attach to it to force the brake blocks off the wheels when the handbrake is released. Is that right? Any suggestions about what it should look like and what it should connect to? BTW: You can also see the balance pipes and part of the water pick-up apparatus in the centre. I know this would have been removed in the period of loco I'm representing but I'd still like to understand it and so I might need to ask some questions about that too soon - but not yet. Thanks for any help anyone can offer,

Whistles: Brake blocks and brake rodding. Leaf spring suspension for driving axle: Rear details: I don't think the top lamp bracket is correct but I don't have anything positive to show how it should be mounted on the enlarged bunker. Still lots of things to do - lots of riveting!

Yes, I know. I didn't say they were stall motors.

MTB MP1s have a lot to recommend them: They have a very simple and elegant mechanism inside - basically a motor driving a camshaft. They switch themselves off at the ends of their travel so they don't make that horrible straining noise made by some (all?) stall motors and they don't consume any power when idle. The internal switches are all discrete sealed third-party micro-switches, so their durability and reliability should be excellent. That includes the built-in frog polarity switch.

This is the underside of my DCC Minories layout. I too used Wago connectors and double row DIN terminals, exactly as discussed above: The "bus" is mainly multi-core copper red-and-black speaker cable from B&Q. It dives in and out of the DIN terminal blocks around the outside of the frame. All the wires are looped around the clamp screws. The Wago connectors are all inside the grey "Wagoboxes" where they are kept neat and safe. Some people hot-glue their Wagos to the baseboards but by using Wagoboxes they can all be pulled out and got at in future if need be. Wago connectors allowed me to wire the layout with frogs switched by the turnouts for initial testing and then to change them over to be switched by the point motors when they were installed. And should a motor fail in future I will be able to go back again.

Same here. Clip strength (when you're not sure what you're doing) vs. glue strength. Clip strength won.

Of course there's an odd one out in that list. The Accurascale Manor sets new standards and all of the other members of that list are lagging behind it in terms of accuracy and detail. Maybe that means that some of those classes, including the twenty-nines, are now commercially viable for updating? I have three Stars, two are OK runners, but Hornby's most recent Lode Star has a "lump" in the gear train that I never managed to diagnose, despite having the whole thing to bits. I hoped that it might wear itself away but I can still hear the hammer blow on the rails every now and then.

I've programmed Thunderbolt to make some random sounds when standing ("Oh Sam!", "She Won't Couple", "Coal Shovelling", and "Safety Valve") and when moving ("Whistle", "Chin up Ollie" and "Safety Valve"). That brings a little bit more life to the model.

Watch out for cheap Chinese screws on the well known auction site. They can sometimes be very soft - fine in plastic point motor bodies but useless in plywood.

If the track planning stage of the project is over, please consider starting a new thread in layout topics or asking the mods to move this one. Thanks.

This is the first I've heard of MP1s failing. Do you know what the causes were? How long had they been in use?

I think you can see the telltale array of studs indicating a double skin: Can't see lines of rivet heads.

The red in particular doesn't seem to look so garish in real life. For some reason electronic photos seem to accentuate it.

I couldn't remember where I had ordered Thunderbolt et al from and I was just starting to worry but it arrived in the post today! Woohoo - I really need cheering up at the moment! (Turns out I ordered it from Rails, who sent it without any email notification or tracking... But hey, it was a nice surprise.) The whole set is superb. Beautifully presented, great support material with a sense of humour and a wonderful little loco and pair of vehicles. (It would make a great Christmas present.) No bits missing or damaged, Modelu figures intact and looking the part. Thunderbolt runs very sweetly straight out of the box but I'm giving her the recommended running in period anyway. Very happy. Thanks to all at Rapido and especially the CAD team.

The colourised photo is also reproduced on a full page of Adrian Knowles' book, "The Wellington, Much Wenlock & Craven Arms Railway". (Page 299)

Remember that any embankment was railway land and so the boundary fence would be at the bottom. That may be why you can't see fencing in some of the photos you're looking at.