Every steam engine that is in regular use has to have an annual boiler inspection. Firstly, a cold inspection with the boiler partly dismantled to enable the inspector to look at the inside of the boiler, then a steam test to make sure that there are no serious leaks and that everything works while in steam.
Every ten years engines have to have a more rigorous examination which also involves a hydraulic pressure test.
Preparations for the ten year test are a bit more complicated. The boiler cladding sheets and lagging material underneath have to be removed to expose the boiler barrel, then the safety valves have to be taken off and replaced with a blanking plate.
The boiler is filled to the brim with water and a hydraulic test pump is connected, this pump is rather like a stirrup pump with a pressure gauge attached, it is used to pump water into the boiler to raise the pressure in the boiler. Hydraulic pressure is used as in the event of a failure, the pressure is released almost instantly and safely.
The boiler is pumped up to one and a half times the working pressure and held for 30 minutes. The boiler is thoroughly examined during this period for leaks, plate bulges and any other signs of weakness and if none are apparent, the test is passed.
Over this winter, Lady pride of England has had her ten year test which she passed successfully without incident. Being a showman’s engine, it is a bit more complicated to strip her ready for inspection. The steering gear, belly tanks, balance pipe and numerous other smaller parts have to be removed before the lagging. The safety valves were removed and a rubber seal was fitted under the regulator valve then a blanking plate bolted on to make the cylinder block pressure tight.
The hydraulic pump raised the pressure to 300 p.s.i. and held it there for the required period while checks were made. All was OK so pressure was slowly released and after draining the water, the boiler inspector made his usual survey which she again passed. All that remains after reassembly is the steam test then Lady will be once again fit for the year ahead.