Thanks for all the suggestions regarding springs and things (and sorry, I the depths of my despair I didn't manage to take any pics of the chassis!), but have got somewhere. In fact I haven't really gone anywhere but the little Simplex has gone around my loop of Hornby set track on the living room floor (in true train set style!), completely unaided and with three hefty white metal D class wagons. I persevered with the pick ups and the real break through came when I had the brainwave of bending them with a needle. What I did was thread the end through the eye of the needle then twist the needle with a pair of pliers. This enabled me to get a good bend in the right place where you can't really get to just with pliers. It is still not completely right though. I can see the paxolin strip flexing and moving under the pressure of the spring and only really stayed in place with the help of a blob of BluTac under the body. To remedy this I think I will build up the contact area for the glue with some lead sheet and kill two birds with one stone. I do fancy experimenting with phosphor bronze wire and making some springs. Should be taking the Father in Law to the Stafford show in a couple of weeks so shall pick some up from Eileen's then.

One thing though - little Iz says it is too noisy and can't go on 'our' railway! That's telling me - I shall have to try and do something about that!