Discussion in 'Steam Traction' started by Ian White, Oct 31, 2017.
Confidence in design and manufacturing? I'm sure our GWR forum members will know.
Gwr enginemen disliked all over cabs funnily enough and rigidly stuck to what was in place.
Brilliant day today in more ways than one with the weather forecasters as inaccurate as ever. 2999 visited all parts of the site and gave rides on the demo line. And the Atlantic conversion was positively mentioned in the speeches. Congrats to the GWS with a new Saint 65 years after the last one was scrapped.
Based on the evidence of the engines they used, the average GWR loco man must have been only about five foot tall (but with six foot long arms) so the cabs probably seemed reasonably capacious to them.
As for tri-cocks: the GWR wasn't exactly alone in slightly odd design choices. The blower valve on a Black 5 is neatly positioned directly above the firehole door, so in the event of a serious blowback, both crew members get an equal opportunity to suffer burns while trying to whack it open...
Ah, but Stanier, the great man himself, was a product of Swindon. Some habits died hard?
I knew about the blower valve on all Stanier locos but to be fair it is a handle rather that a wheel so you can knock it round with the coal hammer or shovel. Bulleid had a much better idea with a long cross-shaft across the cab with a handle at each end easily within reach of both driver and fireman
On the latter point, Bob Meanley has already explained on here that the GWR rigid design of water gauge, with the water column connecting top and bottom valves, ensured that they could not be out of alignment, which was considered to be one of the main sources of failures on independent valve gauges.
The UK practice of needing to run with firehole doors open seems odd when compared with practice elsewhere, and the common use of steam operated Franklin/butterfly doors, with closed being the default position (as initially used on Bulleids I think).
No doubt, though that doesn't explain why the GWR felt that one was sufficient (plus try cocks) while other railways preferred two gauge glasses.
I've always found having the doors open helps with getting the coal in
More seriously, there's probably an interesting discussion to be had there, but I suspect on a different thread.
There's at least one video on Facebook
Looks as if she raises steam and the safety valves work...
As with a lot of things there's a balance to be struck. Two gauge glasses presumably means double the chance of failure. It all depends, I suppose, on how reliable the rest of the design is as regards false indications.
No it doesn’t mean twice the chance of failure, it doesn’t change it. If the chances of one glass going is, say 1 in 1000 and that glass blows the chances of the second one going is still 1 in 1000. It just means the loco fiexng become a total failure.
GW practise was to shut the doors between each shovelfull was it not?
Not at all. GW practice was to use the flap, which is far easier. Opening and shutting firehole doors between shovelfuls is a vastly overrated pastime.
Well yes, but if the chance of failure of a glass is one every thousand trips, the chance of one of two failing is two every thousand trips. AIUI GW crews carried a spare glass and could fit it.
Changing a gauge glass is a basic job which every fireman learns, it takes but a couple of minutes. You should always check that you have a set of spare glasses and rubbers before going off shed.
A glass going does not, as some people seem to be implying, constitute a total failure.
From previous posts on here, the Mid Hants seem to think so.
Regulations on factory boilers have required two means of water level indication since the 1880's. Railways fell outside this requirement but generally provided two.. Even though the GWR provided try cocks, as well as a gauge glass, they were on the same column so a blocked portway would affect both the glass and the try cocks.
No it’s not. If you are on an aircraft and one of two engines fail does that mean you have halved you chance of landing safely? The is no ad the chances of the other one going are still infinitesimally small
The key thing though is that if you have one glass and it breaks, you are "blind" until you can change it. If you have two and one breaks, you still have a water level reading. (The likelihood that two fail simultaneously is vanishingly rare). So even though you can change a glass, if you have two you have bit more choice over when to do it.
Clearly, the GWR wasn't over run with catastrophic boiler failures that could trace their cause back to a crew running without knowledge of water level because of a broken glass. So their method worked for them, but I still find it interesting that by the early twentieth century, all the other major companies had decided that having a second glass was an additional expense or complication worth having.
Separate names with a comma.