Sunday, May 31, 2015

Clayton Battery Electric Locomotive No. 5843

While work is still ongoing to turn the Hudson-Hunslet into a kit I've already started work on designing another model. As with the Hudson-Hunslet I've picked something with local interest; this time to where I live now rather than where I grew up.

As I've mentioned a number of times before the Penistone line from Hudersfield to Sheffield runs along the bottom of our garden. Until 1981 the line also formed part of the Woodhead route between Sheffield and Manchester. The line to Manchester branched from the current line at Penistone and climbed into the Peak District where it entered a tunnel at Dunford Bridge before reappearing at Woodhead and continuing to Glossop and on to Manchester. Since the line originally opened in 1845 there have been three parallel tunnels built. The original tunnel was joined by a second one in 1853 and a new tunnel replaced both of these in 1953 when the line was electrified. When the new tunnel opened in 1954 the two Victorian tunnels were closed and the track lifted and they remained unused until 1966.

In 1963 the Central Electricity Generating Board (CEGB), now known as the National Grid, announced that they wanted to construct an overhead power line linking Thorpe Marsh power station in Yorkshire with Staylbridge in Cheshire. There was significant public objections, however, to allowing pylons to be built within the Peak District and eventually the CEGB decided to route the cables through the old Victorian railway tunnels. As part of this work a 2 foot gauge railway was installed within the northern of the two tunnels to ease access. A number of locomotives have worked this line but my interest has been caught by Clayton battery electric locomotive works number 5843 which was a one off variant of a standard Clayton design using larger wheels to give a higher top speed.

The locomotive was delivered new in 1971 and withdrawn, I believe, sometime during the 1990's. It's now owned by the Moseley Railway Trust who purchased it in 2000. Amazingly these two photos are the only colour images I've been able to find of it in use prior to preservation (there is a black and white photo in issue 77 of the Industrial Railway Society journal). It's not just photos of the locomotive that are hard to find though. Given how much interest there is in the standard gauge Woodhead route I can find almost no published accounts of the 2 foot gauge railway that replaced it. I'm guessing this is mostly due to only short sections at either end of the tunnel being visible to the public and both of these are in fairly out of the way places. If you happen to know of any more details on the line, the locos or the rolling stock I'd appreciate it if you could leave a comment.

Fortunately, while details of it in active use might be scarce I already had a set of drawings done by Jeremy Tilston in 2005 and these have allowed me to make a start on a model. Currently progress is only virtual as I'm again intending to 3D print the majority of the model.

There are still a few details to add before I order a print but the render on the left seems to be a good representation. My plan is to print it in two halves; a chassis (in orange) to which all the mechanical parts will be fitted and then an upper body (in yellow) which will slide over the motor and be secured by two screws. What you can't tell from the images is that this model is in a new scale for me.

I really wanted to produce a model of this locomotive in OO9, the same scale as the Hudson-Hunslet, unfortunately it just wasn't possible. On the Hudson-Hunslet the motor just fitted within the bodywork, unfortunately on this locomotive there isn't enough space in OO9 to fit even a 6mm x 10mm motor horizontally within the body and if fitted vertically the driveshaft would be almost touching the rail and two low to drive the layshaft. This means I've had to move up a scale and this model is designed for O14. For those not familiar with this scale it models narrow gauge in O scale (7mm to the foot) using 14mm gauge track. This has the advantage of being an accurate representation of 2 foot gauge railways. Even in this larger scale the model is very small and in fact won't be much bigger than the OO9 Hudson-Hunslet!

Of course having never modelled in O14, or any scale larger than 4mm to the foot, I'm going to have to see what modelling skills work in a larger scale and which need some more thought. I'm also going to need to build some 14mm gauge track to test it on. I can see months of fun ahead!

Sunday, May 17, 2015

Lazy Sunday Afternoon

Since the weekend I visited Rainford when I messed up the pickups on the Hudson-Hunslet there hasn't been much time for doing any modelling. Today though I set myself the challenge of fixing the pickups once and for all.

My hunch was that the 0.112mm phosphor bronze wire I had was perfect as it was springy enough while having a tiny surface area so as not to introduce lots of extra friction. What I realised this morning was that as the wire came as a coil it naturally curves in one direction and so is springier when fitted one way as compared with the other. Last time I think I had it curving away from the wheels as that was the most natural direction given where the pickups are mounted. This time I've fitted it so that it is always wanting to curl towards the wheel instead. Fingers crossed this seems to work really well as even though it moves about a bit as the wheels turn it naturally springs back and continues to press on the treads. With such a light but continuous contact I've found that the slow running has also improved considerably.

So having finally solved that problem I think I'm now happy with all the current prototype parts; the chassis is easy to put together, the etches fit the body print and nicely reproduce the makers name on the front, and it moves as it can collect power! So the next step will be packaging things up as a kit and working out how much interest their is so I can figure out the size of the first batch.