The Project Gauge 1 Locomotive

Following the issue found on Girton chassis. It was decided to follow the Gauge 1 Model Railway Association "Project" book, which was a fully described design for a single cylinder, high pressure locomotive, designed with a beginner in mind.
This page doesn't detail all the building steps for the locomotive, these are best taken from the book, rather, this page just details deviations from the plans or adds comments to the design which might be helpful to other builders.
To get started, the frames and connecting rods were purchased already laser cut. This time from Walsall Model Industries, who also supplied the wheel castings, buffers and a steam dome for the build.

The valve itself was made to the plans but the valve rod had a shoulder turned down on it, rather than filed flats, just for neatness.

Other changes to the valve gear included a length adjustable eccentric to enable fine tuning of the valve timing.

All of the pivots on the valve gear were made from 8BA screws but with a brass shoulder (made from a piece of brass tube) so that the screws could be tightened to the shoulder to keep them secure.

The lubricator was made to the given design but with the addition of a cylinder drain cock used as a drain valve.

The wheels were "quartered" using the jig developed for the electric gauge 1 loco.
Each pair of wheels was secured to the axle using Loctite.

The connecting rod bushes had to be relaxed to get a running fit. Originally they were 4mm reamed bushes on a 4mm drive pin. However the 4mm holes had to opened out to 4.3mm to get the valve gear to turn smoothly.

The plate parts were made to the plans.

A boiler was purchased from steam supplier "Just the ticket". It came fully pressure tested and certified with external pipes ready to be cut to size.

The smoke stack was made by boring the centre hole and then tuning a thin flange for the base.

The part was removed from the lathe and the flange formed on a wooden block to fit the smoke box.

Then the part was returned to the lathe for the outside profile to be completed, before being parted form the bar stock.

The boiler was lagged with 1.2mm boiler lagging. This was secured with copper wire while the cladding was fitted.
This meant that the smoke box diameter had to be 1.4" larger and so a conversion ring was tuned from a piece of aluminium.

The smoke box door was turned from aluminium to be a push fit in the front.

The burner was made to the plans. For wick material, the latest carbon fibre and ceramics are available from Just the Ticket.
However, some automotive exhaust wrap was found to work well.

The cab plumbing.

The first steam test underway