Shed Turn - Piston Valves

After the Mince Pie Specials finish at the beginning of January, there are no more service trains until the February Half-Term - but I still need my railway fix.

Aside from the odd MIC, this come in the form of shed turns. there is a lot of maintenance to be done, inspections and repairs that can only be made out of season, when the engines can be out of service for a while. This produces a huge demand on manpower and volunteers are encouraged to turn up and help out in the loco shed at Weybourne.

Today I arrived at 08:00 for the start of the normal working day, to find the BR standard 4MT, 76084, undergoing a valve and piston exam. Both valves and both pistons are out on the bench and the liners can be measured up:

Every 28 running days, the loco boilers are washed out. The railway tracks the running days and brings the loco on-shed for the plugs and mudhole doors to be removed and the silt & debris hosed out of the boiler. These mudhole doors have been cleaned up ready to go back on:

This is a loco I have not had a chance to see in close up before.

This is 1982 Ring Haw, and she is an 0-6-0ST built by the Hunslet Engine Company, from Hunslet, now a suburb of Leeds. From the NNR website:

This locomotive was built by the Hunslet Engine Company in 1940 to work at the Nassington Ironstone Quarries near Peterborough which were opened that year. The locomotive was used for hauling iron ore tipplers out of the quarries, usually three to four at a time to the dispatch sidings to make up longer trains ready to be picked up to be taken away on the mainline. Here it worked with another preserved Hunslet locomotive (Works No 1953 Jacks Green).

Both of these locomotives worked at the quarry until 1970 when it closed and were therefore the last steam locomotives to work in ironstone quarries in England.

Ring Haw moved to the North Norfolk Railway (NNR) in 1970 and is currently on hire to the Spa Valley Railway at Tunbridge Wells until January 2020.

As the site says, for most of last year Ring Haw has been on hire to the Spa Valley Railway, so I've not seen her since I started as a volunteer in May 2019.

Here are a few pictures. She's got an extended regulator handle. I guess, as a shunter, you want to be able to drive from both sides. Notice the vertical injectors:

Damper levers and injector water valves:

Blower on the right I guess; not sure what the vertical pipe on the left is.

Pole reverser and vacuum ejector.

The gauges are all out for calibration checks. I guess those linked levers are for the whistle, or for sanders?

Most more modern locomotives use piston valves (rather than slide valves) to admit and exhaust steam from the cylinders. Piston valves, being round, are pressure balanced and do not suffer the operating forces of slide valves, with consequent effect on locomotive efficiency. This is how they are arranged above the cylinder:

Here's one of a pair from the Standard 4MT. You can see the nut retaining the valve bobbin to the spindle caked in carbon from burnt steam oil. In this picture, I have already removed three of the six iron sealing rings:

That's all 24 rings removed.

Just like in your motorcycle engine, the burnt oil gets in the ring grooves and causes the rings to stick:

In a two stroke engine, you peg the rings in place to stop them getting stuck in the ports. These pegs perform the same function:

It took me eight hours to get them all cleaned out...

More next time.