About Comments

Comments are enabled on all postings. Click a posting to find the comment box. Comments are moderated and appear after my review.

Friday, 12 April 2019

0 Gauge 15T Ballast Wagon Hut Carrier

I have trodden the sad road to rivet counting, which I swore I would never entertain because life is too short!

This is my first attempt at scratch building 0 gauge wagons. What can be said about it is yes, greater attention to detail is required than for 00 gauge; I had to remind myself of this being used to 00 gauge modelling. In so doing there are small parts revealed in the analysis that are just as fiddly to create as in 00 gauge! Nevertheless, it has been a rewarding experience since it stretched my design and modelling skills and given insight to another aspect of historical railway practise and vehicles.

The Result (ignore the track. I have not invested in 0 gauge track yet)


Historical Facts

The hut carrying wagon is a SR 15T Ballast Wagon (Diagram 1773) with the drop side doors removed. A few of these converted wagons were deployed by the SR Exmouth Junction concrete works for the conveyance of huts. Most did not carry identification, apart from the number plate fixed to the solebar.

I did not have a drawing of 1773 but I did have a drawing of the steel plated door variant. This has the same overall dimensions and similar chassis. The main differences being buffer style, brake arrangement and four door stops instead of six. This together with several photos of 1773 on the web enabled me to design the wagon. The web photos were of aged wagons showing a distinctly grey weathered finish. I adopted same.

Design (also see modelling referemces at end of posting)

The wagon was deigned as a kit of parts in 3D CAD (FreeCad Application). The image shows the parts for the chassis. Other parts not shown are axlebox, buffer, brake mechanics, door stopper and hut cradle. The parts were 3D printed on my own printer

Buffers

Since my Terrier locomotive has sprung buffers I decided that the wagon would have them to.

The buffer shank is a panel pin and the spring is made of phosphor bronze wire netting from a wine bottle. I wound the wire around the nail to make the spring!

The photo shows the assembly. The buffer head is glued to the pin head. The buffer is glued to the wagon headstock. The shank passes through both and the travel limiter glued to the shank in a position that gives the outward travel required . The spring is placed over the shank and the container passed over this and glued to the rear of the headstock. The shank passes through the end of the container.

These photos show the operation. (top - closed, bottom - open)


Compensation 

Having gone to that effort I decided to include chassis compensation as well. This employs a cradle with a central rocker that gives 1 mm clearance between cradle and wagon floor. There is also 1mm gap between leaf springs and solebar. The rocker also serves to keep the wheels square to chassis. The central hole was only used for position alignment with the floor. (These macro photos reveal the roughness of the 3D print, Not noticeable at normal viewing distance.)

 Below: Normal alignment and compensating for obstruction.

The tie bar is flattened 0.5mm wire loosely held in the axle box frame to allow independent compensation of fore and aft wheels.

Rivets and Coupling

And so to rivet counting, or how to make them. I tried several "fluids' and found the acrylic matte medium gave the best result (yet another use for this versatile substance). Poke a cocktail stick into the medium to pick some up. Offer the stick vertically to the model and twist about half a turn,  lift off to leave a nice round deposit.

Each link of the 3-link coupling was made by wrapping 1mm wire several times around a rectangular bar and then cutting along the set with a razor saw. The coupling hook is a spare from a proprietary chassis kit (presented in next posting). 

I am not sure if I will get on with this authentic wagon coupling method and will need to devise a shunting pole for easy of manipulating the couplings. If that becomes too difficult/tedious I may install the Alex Jackson coupling method across all the rolling stock.

By the way, angle brackets less than 0.5mm thick, like those on the wooden end panel, were made up from thin card and after applying to the model, coated in cyanoacrylate glue to stiffen the pliable card.

Hut Cradle

There is speculation from an obscure photograph that cement bags were used to protect the corners of the concrete huts from the cradle compression. I choose 'Blue Circle' bags and applied the logo that was in use before 1967.
Cost

I suppose I should talk about the cost to make the wagon since 0 gauge proprietary products are notoriously expensive.


Plastic: £0.62
Peco wheel set: £8.03 (discounted RRP)
Extras: pennies

Total: Less than £9.

If such an 0 gauge wagon was available RTR from the trade then probably around £50 or in kit form £35.

What I have not accounted for is the hours and hours gone into the design and build of my model and the overhead costs. Perhaps that can be negated by the pleasure derived from the hobby.

Mistakes

The width of the wagon is about 1.5mm too wide because I used the dimension from the outside of the (unfitted) side doors instead of the inside.

The brake lever is partially on instead of fully off for a moving vehicle.

References

Concrete PW Huts: The Model Railway Journal #62
Non Hoppered Steel Ballast Wagons: Model Railway Constructor, December 1984
Compensation for 0 Gauge Wagons: Railway Modeller: June 1984
Paul Bartlett's Photographs.

Postscript

When I get around to a making a model railway layout I have a vision of some prepared ground with a couple of workers peering into the distance awaiting  arrival of the huts. And when they do arrive they will still be peering into the distance awaiting arrival of a travelling crane to lift and position the huts, which may never arrive!

Next up is a Mineral Wagon.

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...