Saturday, 19 March 2016

Maintenance Update (grease, valve, clack)

Wednesday 16th
I’d had this great idea to give volunteers, especially the newer ones and those who have helped with 2807 over the winter, a free ride on the footplate. You see, we have race trains this week, and 2807 is on standby (i.e. in light steam). Also, there is nothing happening between about 1pm and 3pm while races are on and our trains are idle. So, I spoke with all of the key people at GWSR and obtained authorisation to operate 2807 between Toddington and Winchcombe. Jeff and Ben volunteered to crew the engine, and we did most of the prep. Roger Tipton [Loco Dept] lit & tended the fire.

Not everything went to plan! There were not many volunteers at Toddington - whether they figured little would be there for them to work on, or whether they were working on race trains/marshalling/etc., I know not. Furthermore, by virtue of assumptions made, no one actually advised the signalmen … so he at Winchcombe knocked off and closed the box!

Nevertheless, half a dozen chaps did get a number of rides up & down the running line at Todders - including the two chaps (Keith & Graham) in the workshop, who only see the light of day when they arrive & go home!

Gil, aided by Phil [Loco Dept], dug through the muck and uncovered the grease points - which look as though they had not been greased for many a month! This raises a concern, that crews may not all be familiar with grease points (or perhaps even oiling points) on all locos that they may be asked to work on. I think that we would be well advised to undertake an all-round greasing once per month, regardless of whether crews have or have not.

Bruce oiled up. He was delighted to see that the pony underkeeps were still full to the brim! He checked the injectors - no leaks; he checked the pep pipe - no leaks; and he was most happy about the clack valve.

John G was painting the chairs in the boot scraper production line. He did get a ride on the loco, but also took an unnecessary walk to Hailes … hoping to video the loco between Todders and Winchcombe … that was before we discovered that Winchcombe box was switched out!

Later, he had another go at polishing the driver-side number plate to get the last bits of varnish off.

We checked the pony wheels, and they have a lovely shiny stripe right round the middle of the tyre (phew!). We checked the rocking shaft and nothing amiss there. The crew applied the tender brakes gently, in order to bed-in the new brake blocks.

During the preparation stage, we tested the steam heating relief valve and that blows at 40 psi, as it should (even though the glass has a red line at 60 psi). Unfortunately, the main safety valve blows at 200 psi instead of 225. We shall have to fix that, because it will confuse the crew if they expect 225 and only get 190 before the valve begins ‘feathering’. There is a very minor steam leak at the tender-side flange of the steam heating connection. It could be the weld, or possibly the gasket.

Alan came and carried out Portable Appliance Testing (on electrical apparatus) during the day. A couple of items failed because of poor cables; and I gave up trying to fix the inspection lamp.

Saturday 19th
We appear to have run out of things to do … so Bruce & Gil tidied up the workbench and table in the TPO. Things had been ‘dumped’ thereupon (as they do) … tins of nuts & bolts; tins liberally coated with oil; oil in a tray with a brush stuck in it; a nut that was going to be used …

Bruce is going to make a spanner to fit the clack’s set screw. These have a square head, and when you tighten them (hard) you tend to use an open-ended spanner and a mallet. But these spring and can also sprain. A ring spanner, however, is not designed to fit a square head; so Bruce will make a ring spanner to fit the square head.

He measured the width of ours (0.82”) and also that on 4290. Guess what …. Anyway, Bruce decided to make the spanner to standard size (11/16”), and (in due course) reduce ours to standard, too!

For those of you who have given up wondering what on earth a “clack” is, here’s a quick intro: It’s purpose is to deliver water into the boiler and not let steam out. The injectors force water up pipes around the boiler and into the clack box which is at the side of the safety valve mounting. The clack valve is circular and sits in a cage in the clack box. Steam pressure holds it down on a seat (that Bruce keeps lapping to get a very close fit). When the injector forces water through, the water passes into the steam space of the boiler and onto a sequence of trays that slope towards the front of the boiler. This allows the water to heat up and also for any air or solids to be released, before it is scattered off the trays into the water towards the front of the barrel, which is the coolest part.

Anyway, it was too cold to play on the loco, so I just painted the boot scrapers!


1 comment:

Anonymous said...

Does anyone have a works drawing of the clack please?