In this particular case yours truly was not prepared to compromise on either of the locomotives which are being constructed. A 16 spoke wheel of the correct diameter is not available for the Wainright H class as preserved on the Bluebell so it has to be the Stirling Q class. The MR Johnson needs a new wheel pattern and this will be available in 2012. Part 2 will review the prototypes that you might want to select, information sources, plans available and illustrations of some of the engines. Part 3 will review the off-the-shelf components and where to get them, plus construction and design considerations. Ginger - December 2011