Boiler Washout

401 has been out receiving a boiler washout today

Katie begins washing out with the pressure washer, starting in the smokebox and blasting along the top of the boiler tubes

Same at the other end, washing down the top of the inner firebox crown. Any sludge and scale etc is washed down to the foundation ring and raked out

As the loco is due an annual exam this month the dome cover plate has also been removed, giving an opportunity to take a look at 401s double beat regulator valve. This photo shows the regulator in the closed position

Regulator fully open, video showing its operation below

Two valves are cast in one vertical cast-iron pipe in the dome. When the valve is opened steam is admitted past both top and bottoms seatings at the same time, entering the lower seat by passing through the centre of the valve