Last seen on arrival in January (An Avalon Arrival), work has finally progressed on the pre-built Avalon Line locomotive that I acquired from 7mm NGA secondhand sales. Since the last post my theory that the model had been built and finished by Steve Bennett has been confirmed via a contact on Facebook. Apparently there were several models in the Avalon and Black Dog ranges finished in this way for direct sale, making this an interesting bit of O9 history.
I also left the last post on a bit of a cliffhanger in relation to my plans to power the model, whether to try and repower a Farish 08 chassis or investigate using a Halling 21mm wheelbase unit. As you might guess from the title, the Halling unit won. Due to the way the postage charges work it makes sense to order more than one at a time, so I acquired units for some other projects too.
As they come the modern Halling units are tiny, even compared to the Kato 'core' from their modern chassis. There really isn't much to aid fixing it in place in your chosen model so I had to carefully plan how it would fit into the void of the model. The solution is seen below...
Taking things at first principles, I opted to create a sub-frame and carefully measured the space available under the loco body and the space the chassis required to 'clip' into something (there are clips either side of the motor). With a few scribbled plans I found could suit both (just), with only 1.5mm difference at either end. I marked out and cut a piece of 40 thou styrene to which Evergreen strip was then added above and below this to strengthen it. Once set a "nibble" was taken at either end to fully clear the worm gears. Below this recess is a small 20 thou piece that firmly holds the end of the chassis under the worm.
Platforms extend at either end sit onto the positions within the body designed to accommodate the Farish chassis. The joins for these are re-enforced to hopefully prevent sagging. Two tiny screws in opposing corners hold the sub-frame in place within the loco. In the recess above the frame I added some adhesive window lead strip to add some weight, and also added more strips behind the sideframes of the body. A further piece of lead in the bonnet end is ready to counterbalance a whitemetal driver figure, currently undergoing surgery!
More soon.
Colin