Saturday, 9 April 2016

Maintenance Update (heating, conduit, block)

Wednesday 6th
With 2807 still in service, there was little to do but boot scrapers. But Bruce did take advantage of the lunch-time lay-over at Toddington, and check out a few things:

We were convinced that no one had set the Mason’s Valve (for steam heating) to a correct pressure. After fitting a new diaphragm within it, it does need testing & setting (which can only be done when in steam). So, Bruce checked that. Sure enough, crews had been ignoring the valve and just turning steam on/up/down using the on/off handle! Bruce set that to roughly 35 psi. The relief valve blows at 40 psi, anyway.

Concerning the audible hum from the pony wheels, Bruce examined the axleboxes - barely warm; underkeeps - not moved & not rubbing on anything; tyres are shiny down the centre (so pony is no longer drifting sideways). What he could see, was faint score lines across the width of the tyres. Almost certainly caused by “chatter” when they were machined. This could well be the cause of the hum. We listened as 2807 passed by, and Bruce reckons that the hum is still there, but fainter than it was. The net conclusion being that no action is necessary. The imperfections in the tyre surface will wear away on their own.

Skip to Saturday: Photo shows the LHS pony wheel. The jitter in the cutting is now clearly visible. It is largely worn away down the centre, which shows that the pony is running centrally now (thank goodness!).

Back to Wednesday: Bruce and I cleaned up 5 rail chairs (including an LMS and an LNER), whose bottoms John G subsequently painted black. John also applied Deproma (primer) to the top of three chairs from last Saturday.

John & I examined the AWS conduit at the front of 2874. We found that the front section is consistent with 2807’s. We don’t have the very front part, between detector shoe and the side conduit, but we were able to make a template from 2874’s. We have a spare piece of conduit that can be bent to shape, so I popped in at Dan (the blacksmith) to see if he can do that for us.

Over lunch, we mused about 2807 possibly being the longest serving GWR loco that is still extant. Running from October 1905 until March 1963 (nearly 58 years), is there any other GWR loco that could have been in service for longer? We thought not! It would have to have been “born” pre-1909 … but it turns out we were not quite right:-

  • 2516: Dean Goods, built at Swindon in March 1897, withdrawn in May 1956 = 59 years!
  • 2818: built December 1905, withdrawn October 1963 = 58 years;
  • 3440: City of Truro, built May 1903, withdrawn June 1948 = only 45 in GWR/BR service;
  • 4003: Lode Star, from 1907 to 1951;
  • 9017: Earl of Berkeley was not actually (re-)built as such until 1938, so that doesn’t count!

Saturday 9th
2807 was out of service so that we could have a play. Bruce & Gil decided to examine the brakes. Those on the loco needed adjusting a little - which they did. The tender then took up the rest of the day! Two problems: The centre LHS brake block was jammed in its hanger, and not free to swing (as it should); the new brake blocks appeared to be scoring the tyres.

Gil ground off some of the heel of the errant brake block, to make it fit freely in its hanger. Our tender has 3 different sorts of hanger, the middle ones (both sides) are narrower than the rest.

There is a visible score line which we thought might have been caused by the new brake blocks not having been profiled to match the tyres. The blocks came square; tyres are not! However, we cannot prove that this is the cause. It would really make sense to ensure that blocks are profiled in future. It is impractical to profile them by hand - using an angle-grinder, for example!

How many people does it take to fix a brake problem?

Meanwhile, I busied myself with boot scraper manufacture most of the day. I did take a butcher’s at the AWS conduit, again.

The curved section ahead of the pony we do not have. I have asked the blacksmith to make us one.

The bit that we do have for connecting to the bell in the cab … is clearly not from 2807! It doesn’t reach.

2807 is now scheduled to be in service Tuesday 12th to Thurs 14th; then Sat & Sun 16/17; and then for the 40s weekend on 23/24th April.


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