Hi Fizzy ,

My 3 1/2 inch gauge Tich has :

11/16 inch bore by 1-1/8 inch stroke cylinders .

2 inch diameter wheels and 2-1/2 inch diameter boiler .

Design also allowed 3 inch diameter boiler if preferred .

So 7-1/4 inch gauge boiler pro rata is going to be 5 inch to 6 inch diameter . Boiler is very much like your existing steel one but possibly a bit shorter .

Original idea of Tich was to use 2-1/2 inch gauge parts for a 3-1/2 inch gauge engine . In a similar way you could use 5 inch gauge parts for a 7-1/4 inch gauge engine .

One person at least has made a Tich variant using Simplex cylinders and boiler .

Tich in 3-1/2 inch gauge has a certain charm but it seems to become ugly in larger sizes . Personally if I wanted to build a 7-1/4 inch gauge very small engine I'd base it on a real industrial engine prototype – it would still be very simple because the real ones were .

If thinking about an actual industrial engine you may like to find one with some personal association . Like one used years ago either locally or in one of your places of work .

I'm spoilt for choice down here in Swansea – there were hundreds of different industrial engines and I even saw some of them working .

Purely as a matter of interest the original Tich was designed by LVP Clarke and not LBSC .

Regards ,

Michael Williams .