Other than a rear vacuum pipe, this one's about done, and I'm very satisfied with the way the model's come out.

After a lot of testing, I added an additional set of pickups to the rear truck, and this seems to have made the running pretty much 100% reliable, even over some less than fantastic track joints, so I'm well pleased with that aspect of the model. The SWD sound decoder is incredibly good fun, the only downside being that I'm so impressed by it that I've started considering adding sound to some other engines that were already considered done and dusted - a potentially slippery slope. It used to be that I was content with one or two sound fitted engines just to add a bit of interest now and then, but there's something so convincing about these latest steam decoders (in my view) that I fear I've gone over the tipping point. It's hard to articulate it, but because they almost demand that engines be driven with slow starts and stops and realistic final speeds, they make the layout as a whole seem larger, and it's fantastic to hear the way the acoustics change as the trains move from embankments to cuttings, tunnels etc - it really does make a heck of a difference.

Thoughts on the project as a whole: the Comet chassis goes together very well and is - thankfully- spot on in terms of the relationship between the wheel centres and the coupling rods. The main problem I had was with the slide bars, which - being the standard Comet fitting - are a bit too close together to work well with the swing of the connecting rod, given the crank throw of the drivers. The solution I came up with was to flare out the ends of the slidebars slightly (up and down), just to give a fraction more clearance. I also struggled with the slidebar bracket, it being too tight at first, squeezing the slidebars, but after some filing I got there in the end. One defect is that the bracket should line up exactly with the bracket casting which sits above the footplate immediately in front of the tanks, but in this case it doesn't quite correspond, being slightly too close to the cylinders. It's something that could be fixed on a subsequent build, either by ignoring the etched guides on the slidebar, or spacing the slidebars a bit further back from the cylinders with a packing piece. But on the whole, it's not that noticeable. The DJH gearbox and motor are problem-free as ever, and very easy to work with.

As mentioned in an earlier post I kept encountering derailment of the front drivers, for some reason, and it took me a while to track down the problem. I thought it was due to insufficiant weight over the drivers, but it wasn't. I eventually realised that the problem had only arisen after I swapped the smaller pony wheel for one of correct diameter. Even though the front pony truck itself was staying on the rails, it was able to nudge the cylinders enough to occasionally throw the main wheels off the rails. The solution was to grind a little rebate in the front face of the cylinders, and that was the end of derailments.

One nice thing is how well the Comet chassis fits into the Airfix body, and the designers have given a lot of thought to how you mount and retain the chassis, with two suggested methods, which is nice. With the chassis screwed into place, it all feels reassuringly solid, almost like a heavy RTR model. It pulls well, too. The five-coach rake of Toplights and bow-ended stock is heavy, stiff om bends, and can induce a little wheel slip in Hornby Castles and Bachmann Halls, but the 61XX just walks away with it.

Ignore the incorrect headcode, I was inspired by a BR black 61XX in a Barry Freeman painting on a goods service, so that's the main duty this one will end up on, I think.

By rights I ought to crack on and tackle the SE Finecast Prairie next, which I expect will throw up a bunch of subtly different problems, but I may work on one or two other projects before returning to Mister Churchward's finest. However, as they say, watch this space.