1:12 Heywood 15" gauge Brake Van...

[RoughboyModelworks]

Today I finished the CAD drawings for the primary frame components on the Heywood 15" gauge brake van. This project will hopefully be my entry for Russ' "Build a Small Caboose" challenge for the 2010 Annual. The air brake system is a relatively modern addition, added during the 1960s by Michel Jacot and will not be modelled. The original brake was a simple mechanical screw-activated system, operated by the crank which protruded through the top of seat structure between the seat backs. The van is small, 6' long, 3' wide and 6' high, which in 1:24 means 3" long, 1.5" wide and 3" high... tiny, tiny  



I'm using Mike Decker's excellent 1997 drawings of the van as a primary reference source in addition to a few vintage and current photos. The above photo was taken by Simon Harris at last year's steam up at Eaton Hall in July 25th, 2009. The first image below shows the basic frame drawing with all joinery indicated. Lot of mortise and tenon joints to cut here...



The next shows a preliminary rendering of the assembled frame components.



In this view the tongue and groove floor boards are shown in place and again in the rendering below:





Goal is to replicate as closely as possible the joinery and construction of the prototype in the model. This project was the primary motivator behind building the new sled for the Preac saw. More photos and information are published on the Roughboy blog.

Paul

[Chuck Doan]

Looks like a neat project!

[finescalerr]

Paul, if you and Marc and others from this forum enter the 2010 Modelers' Annual contest, nobody else will stand a chance! For that reason my advice to everyone here is ...

Build a small caboose, guys!

Russ

[marc_reusser]

Paul,

You give nice CAD ....
I can see this will be a really neat and educational build.


MR

[lab-dad]

Man I do love that 3-D see through stuff!
FWIW:
What about using the holes/railing to hold the tenon from the side rail into the end beam?
Really cool project.
-Marty

[Brian Donovan]

Very cool. While you're at it would you build me one too? 
It would be perfect for a Gn15 mini layout I just started.

-Brian

[RoughboyModelworks]

Thanks guys. Marc... I thought we agreed you were to never mention that in public... 

Brian, if there's enough interest in the project, I may consider making more than one...

Marty: The transparent CAD makes it very easy to see how assemblies are built up from their individual components and errors in design are readily apparent. It can get a little confusing though as the drawings get more complex, so you have to be selective with the transparency which the CAD application allows. You're right, fixing the tenon with the railing shaft would make a lot of sense, but according to the research, the builders didn't do that. My goal is to build it as close as possible to the manner in which the prototype was assembled. This equipment was built for an estate railway and money was really not an object. As best we know, the rolling stock was built in the estate shops, most likely by cabinet makers. It was built to a high standard, more like furniture than the way we think of most rolling stock of the period. There is a lot of fine joinery work on all the Heywood rolling stock and I'm trying to replicate that - perhaps an exercise in madness, certainly one in eccentricity...

Paul

[RoughboyModelworks]

After a week of additional research and discussion of the joinery work between the frame's structural components with Mike Decker, I've revised my earlier drawings of the frame.

Concerning the joinery between the sole beams and the end beams, the double, captured mortise and tenons have been replaced with a single mortise and tenon open at the top. Additionally, the raised portion of the sole beam is now a separate piece, significantly simplifying the construction of the joints. This piece also has a rebate cut along the inside lower edge which captures the ends of the floor boards minimizing moisture intrusion into the ends of the floor boards. The revised frame is shown below.





Images below show the revised frame with the floor boards in place.





Next it's on to the superstructure...

Paul

[finescalerr]

The rendering looks so good, why even bother with the model? Seems as though it would be almost anticlimactic.

Well, I guess you can't roll the image down your right-of-way. Never mind.

Russ

[RoughboyModelworks]

Quick update. I've completed the CAD work on the cab superstructure. Rendering below shows the completed framing in place on the main van frame. The ship-lap planks in the cab side are included in this view.



Drawing below (it's an anti-aliased screen capture which is why the lines aren't very crisp) shows details of some of the joinery work on the main frame components plus the ship-lap joints in the siding. All the main structural components are assembled with mortise and tenon joints. The joints between the pillars and frame and between the pillars and the upper sills are also pegged.



Rendering below shows the assembled superstructure framing without the side planks.



Next, it's on to the back-to-back bench seats. Beneath the seats are small storage areas which are accessed through floating-panel doors, one under each seat, presumably a convenient spot to stash the ploughman's lunch and a restorative pint... 

Paul

[RoughboyModelworks]

Just a quick update. Continuing to work on the CAD for the "interior" seats and cabinetry. Probably post an update showing those assemblies shortly. I did just receive some fresh Swiss Pear stock for the project. Since I no longer have access to a full-size table saw, I needed to find a source for the wood who would provide stock machined to dimensions that could be resawn in the Preac. My original supplier couldn't do this plus they instituted a $100 minimum order charge which was also unacceptable for my limited needs. I went with The Lumberyard for Model Shipwrights and am very pleased with the stock they provided. Grain is very straight, dimensions are accurate and colouring generally consistent. The surface marks you see are machining marks from the supplier and will be removed as I machine the pieces for the van.



3/20/10 uploaded better photo of the Swiss Pear stock. Shot outside this time in better light, it more closely represents the raw stock.

Paul

[Chuck Doan]

I'll be interested to see how that wood looks as you go. How does the hardness compare with say, Basswood?

[RoughboyModelworks]

It's much harder than bass Chuck. It machines precisely, like metal, is fuzz free and has minimal visible grain. Bass is quite soft in comparison and has a high "mulge" factor. In other words it tends to squish and compress when cut or machined which makes it much less precise.

Paul

[RoughboyModelworks]

Managed to get a little more time with the CAD software and finished the drawings and renderings of the bench assemblies for the brake van. Additional images and more information are published on the Roughboyblog. First image is the bench assembly construction as seen from underneath.



Second is an overall rendering of the van structure with the bench assembly in place. The floating panel cabinet door is open in this view giving access to the storage area beneath the benches, just enough room for a stout Mackintosh, a ploughman's lunch and a pint!



Next step is to sort out the roof construction. Just received drawings, courtesy of Mike Decker, of the wheel profile and various other mechanical components such as the truss rod hardware and crank-operated brake hardware. Tackle those after completing the roof.

Paul

[RoughboyModelworks]

Finally found some time to complete the CAD work on the superstructure for the Heywood Brake Van. Roof is now in place. This completes all the wood components of the van. Astute observers will note the roof is different from that on the current version of the van and is based on information taken of the original van before the roof was rebuilt in 1981 for the Minimum Gauge Exhibition at the National Railway Museum in York, UK. The roof was covered with painted canvas for additional weather protection. I have left that off of the drawings in order to show the structure of the roof and its framing.





Next step is to tackle the metal components: axle boxes, truss rod brackets, couplers, brake system and handrails. Apart form the handrails, all these items are candidates for the PAP process. Though the final components need to be in metal, I'm considering using the PAP parts as masters for having the pieces cast. Fortunately I have measured construction drawings to start with for these items courtesy of Mike Decker.

Paul