Thanks to everyone who chipped on with ideas for pony truck springing - I'll enjoy experimenting with them!
As several people mentioned that they still have Gibson kits in progress, the following might be helpful - not so much what I did, but what I would do now following my experience with "Lew":
- the new Romford/Markits brass outside crank assembly looks a lot more robust and foolproof than the Gibson plastic ones, and using the Romford 14mm axles means the wheels are automatically set to gauge and with far less risk of wobble than the push-fit Gibson ones. The downside is that, unless you're using separate hornblocks, the frames have to be built around the wheelsets, but that has not been a great problem with other kits I have built.
- the cowcatchers are very difficult to do, especially mounting them end-on to an already detailed chassis. It would probably be much easier to leave off the buffer beam overlays when building the underframe, and then build the cowcatchers on to them "on the bench". The complete buffer beam/cowcatcher/vacuum hose sub-assembly could then be superglued onto the underframe at a later stage.
- with 14mm gauge, clearances between the underside of the boiler and the lead driving wheel flanges are non-existent. You may need to carve away a bit of the boiler with a mini-drill to avoid the risk of a short-circuit.Luckily the affected area is virtually invisible in normal viewing.
- the kit's Joy valve gear is a so-and-so to assemble, and can easily bind on the connecting rod and then either seize up or unwind. Correct alignment of the connecting rods parallel to the frames is essential. I failed on this, plus the crankpin holes in the return cranks were over etched, so eventually I gave up. Now my "Lew" has inside Stephenson valve gear actuating the outside valve chests by intermediate valves rods and rocker shafts, Swindon-style (to assuage my guilty conscience I did add dummy rockers behind the valve rods!). I like to think this isn't too far fetched. The Joy gear on the original locos gave good valve events but was maintenance hungry, so the SR could have sought a better arrangement. Stephenson gear had worked well on the Baldwin "Lyn", and the Pilton shed staff were familiar with it. Moreover Harry Holcroft, Maunsell's chief technical guru, was ex Swindon, so would have known the Churchward arrangement well. Anyway, that's my story and I'm sticking to it!
Despite all the above the kit can be built up into a very satisfying loco, so have fun!
Allan
Allan Dare