Since my last entry I have made more progress but it's painfully slow. I did have a good photo of a railmotor chassis which looks to be taken outside Swindon works. I had been using this as a basis for the model but now I'm not so sure whether this is the right thing to do. The GWS railmotor was built from plans so must be correct and there are many photos on their website but there are subtle differences from the photo I was using. In particular on the photo the frames protrude beyond the cylinders but on the GWS example the stretcher is flush with the front of the cylinders. The Nu Cast kit also had this. I had thought that the steam railmotor chassis were much the same (apart from the first two built) but now I'm not so sure. Yes I know I should have read the book on the subject but there's little I can do to change the chassis and valve gear even if they are incorrect. I did also notice that the on the Nu Cast kit the valve spindle and the shape of the cylinders seemed quite different from the photos. The upshot is that the chassis is something of a hybrid. If anyone brings out a nicely etched chassis complete with all the valve gear then this one will be dumped.

In my last entry I had just completed the frame that would locate into the body allowing free movement without the chassis dropping out. I turned my attention to the valve gear adding some sort of reversing lever that I had omitted originally. The slide bars fit into the cylinder and I had to drill the holes out a little to ensure they were firmly located. I made sure the slide bars were in line with the cylinder and temporarily held the assembly against the chassis to ensure everything was i line and the clearnces were OK. I was glad I had drilled the hole in the chassis for the screw on the cylinder as it meant that the position of each cylinder was consistent when checking clearances. I had to check carefully that the wheel behind the slidebars, when fitted with the coupling rod, did not foul the slidebars and crosshead. In fact a great deal of time was spent making sure clearances were adequate. Because of the small clearances I had to make sure there was no play in the axle behind the slidebars. Using the old wheels was useful here as I could take the wheels on and off to add spacing washers until I had the axle running freely without any play. I do find that if you take the wheels on and off their axles they lose their tightness and can in fact become quite loose. Once I had established the number and thickness of washers these were put in plastic bags, one for each side, to be used with the new wheels.

The motion bracket fitted farther behind the front wheels than I would have liked and again this did not match the photo I had. I had prepared a piece of NS scrap (from the fret of an etched kit, I never throw them away) with rivet detail and the representation of the springs. Because the motion bracket fitted farther behind the wheels than on the photo I had to move the springs closer together and cut of some of the NS. Once satisfied that the size was correct I araldited the assembly to each side of the frame making sure there was room in front to attach the motion bracket. I did not use solder as I could see the white metal parts coagulating into a blob and I find Araldite better than cyano which seems to require perfect conditions to work. Araldite is more forgiving.

Before painting I added double sided copper clad sleepers to each side of the frame; these will carry the current collectors. I soldered a piece of NS scrap (more fret from a kit) to the back of the sleeper and then soldered the NS to the frame. I thought that if I soldered directly to the copper it may delaminate as the soldered join is very small and the copper is not always securely fixed to the paxolin.

On to painting, my preference is to use a spray primer and then Halfords matt black, again sprayed. i did the cylinders first using Maskol to ensure the back face which locates against the frame is left bare. Once I had dione this the slidebars were fixed into position permanently, well not so permanently as the lower slide bar on one cylinder needed fixing. Unfortunately on one cylinder the lower slidebar hole had come out of the bottom of the cylinder so it needed some Araldite to fix the slidebar in place. (You can see this on the photo). On the chassis I used Maskol to protect the bearings and those parts of the chassis that would be Araldited. You can see where the cylinders go but looking at the photos I realise that I need to take off the Maskol behind the leading wheels. This is where the motion bracket locates. Unfortunately in taking off the Maskol around the sprung bearings one of the springs came away and was stretched. Hunting around I found a spare spring which I had to fit which in turn meant unsoldering the keeper wire under the bearing. Must be more careful in future!

The photo shows the chassis and cylinder / valve gear assembly ready to be put together. My first job though is to fit the front drivers complete with coupling rod attached and all the necessary spacing washers. These wheels are totally inaccessible once the valve gear is in place so everything has to be correct. In particular I need to ensure that the crankpin does not stand too proud as it could foul the crosshead. Fitting the motor is the easy part. Once the front drivers are fitted the cylinder and valve gear assembly wil be fitted to the chassis using the screw and Araldite. A stroke of luck was that the front of the cylinders lined up with the front of the frame so it does look like the GWS example. I added a stretcher of scrap NS with some rivet detail punched on as this is clearly on the GWS railmotor. I had also been thinking about brake gear but nothing is apparent on any of the photos I've seen. The brake blocks could be tucked away behind the valve gear but if I can't see anything on the photo you won't see anything on the model.

Looking back on work to date I have to confess some disappointment that parts of the chassis in particular the valve gear don't seem to tie up with prototype photos. The photo attached is also a little cruel, the chassis doen't look that bad and once tucked away under the body a lot of it will be obscured by the valve gear. I felt I could have done a better job of the springs but if you aren't sure that the photo you are using as a guide is correct for your model enthusiasm does wane.

Hopfully my next entry will have a photo of the completed chassis. I'm looking forward to seeing that valve gear in operation again.