I can definitely recommend the High Level Pug chassis. I built two in tandem and they are a joy, very clever design for concealing and holding the gearbox in the firebox, full cab detail and removable brake rodding. Mine have the 108-1 gearing and they crawl along beautifully. I used the Alan Gibson wheels which have imparted a slight 'waddle' to the movement which apparently is quite prototypical! (Photos by David Brandreth S4 Society)
I got the bodies (Hornby) from Peters Spares.
I got the bodies (Hornby) from Peters Spares.