A Darjeeling Himalayan Locomotive in 3½ Gauge

Keith Rogers tackles a project that is even more complicated than it looks!

- Keith Rogers

When an article by Ray McMahon describing a turbo generator appeared in 2010 I thought it an interesting thing to make as I had no other projects on at the time. It all went quite well and I even managed to source the hand held torch for the generator. Having made it I thought ‘what am I going to do with it?’ Then Ray’s series on building the Class B Darjeeling Himalayan locomotive appeared in Model Engineer.

Four wheels, outside cylinders - it looked easy. I sent off for the drawings and was shocked when 170 A4 sheets arrived and I began to wonder what on earth I had let myself in for. After recovering a little I thought ‘you’ve bought the drawings, which cost quite a lot of money, might as well get on with it’.

I ordered the laser cut frames from Blackgates and made a start, slightly disappointed that the hole positions had not been spotted. Later, I ordered the cylinder castings and it appeared that most of the other castings listed were unobtainable at the time. Ray made his cylinders from solid lumps of cast iron. On the castings I had, the draft angle used contracted the front end of the cylinder to the extent that I had to reduce the diameter of the front cover and adjust the pitch circle diameter of the securing bolts. Giving up on castings, I made the wheels from cast iron blanks and from another piece of cast iron I bored and machined the brake shoes. I fabricated the two pumps from brass, together with the associated cross member.