15th March


An unusual view of the smoke box main steam pipe connected to the super heater header castings with the super heater elements attached.  The regulation housing would be fitted between the upper most flanges.

All of this is normally hidden in the smoke box and boiler flue tubes. It is assembled ready for hydraulic (water Pressure) test.

Items of note are the very convoluted main steam pipes, welded steel pipe fittings in this case however Swindon would form these from copper (somehow!)

The upper most ends have captive 3 bolt flanges and spherical olives that allow the joints to be accurately made against spherical seat rings on the regulator housing. The loose 3 bolt flanges have the same effect as a 3 legged stool.

The super heater header is a complex casting where “wet” steam from the boiler is kept separate from the superheated steam after passing through the super heating elements (the smaller tubes to the rear)

This is a single row, 6 element arrangement


Just waiting the chimney, regulator, main steam pipes and the superheating arrangement to be installed to complete.


Piston valves now all installed and clad. Shown here is the outer end of the valve spindle, the nut holds a replaceable ground sleeve on the valve rod on the exhaust (low pressure) side of the piston valve. There is one at both ends of the piston rod either side of the valve heads. The high pressure steam is between the 2 valve heads on the valve spindle within the piston valve assy.


The jumper ring on the blast pipe cleaned up ready for further service.
The jumper ring allows a sharp exhaust by the ring lifting under load to increasing the blast orifice but as the exhaust rate decreases, the ring drops back thus reducing the blast. This is a standard GWR fitting.


New Crank pin retaining washer being fitted, It is screwed onto the crank pin and “fitted” by machining the back face off until the tapered cotter pin (not shown) screws in correctly to lock the main washer onto the crank pin.