Discussion in 'Steam Traction' started by 5944, Jul 22, 2020.
Not interested in the insurance inspector's gig then, Simon?
HEALTH AND SAFETY GONE MAD!!!!
Tightening up of clearances has been going for - well, since forever. The LSWR loading gauge was less restrictive than the BoT in the platform area, so clearance had to reduce. A major mistake, IMHO, as it is the lower half of the loading gauge where GB differs most from UIC*. (Probably for the same reason as the decision to continue with Vacuum brake, rather than Air - All Too Difficult.)
*As a freighty I'm more interested in the restrictions on freight vehicles which in many cases is due to platform and underbridge clearance.
I didn’t say that.
Both inform the other, and other laws and acts including accessibility inform the whole.
As always, it’s a balancing act.
Does that mean that sliding doors are less safe than hinged ones?
When the Eurostars wre cleared for use on KX - Leeds runs, our office had been tasked with carrying out the realignments through the station platforms between Doncaster and Leeds.
On one particular platformwe had to slew the track away from the platform about 100 - 150mm due to the centrethrow f the stock.
Now imagine the commuters on the next days train to Leeds faced with an additional wide step to get on their train.
That was down to a Railtrack design scheme.
There seems to be a desire to point the finger, as it were, without considering all the facts.
In the round, it is plain that old railway infrastructure and a mixture of rolling stock across ages will create anomalies in the desired output: which is train, track and platform interface in harmony to agreed standards (which as time goes on, gets updated).
It is not possible to get complete harmony sometimes, so derogations are given where changes cannot be made to meet the railway group standard/act of parliament/level crossing act/etc
This has been the case for decades and almost everything is on a case by case basis.
It is easier to design and build new (e.g. hs2) to achieve the standards as the mix of rolling stock will not likely occur. The compromises happen where mixes of trains and older infrastructure interfaces happen.
The Japanese and Chinese have the right idea - their high speed systems are strictly high speed trains only and there is no crossover or sharing of the track with old rolling stock.
At the end of the day, companies like Network Rail are here to run a service for their customers. They’ve been flexible in the past- likely will continue to do so - we criticize their approach as steam enthusiasts at our peril, as they would be well within their rights to turn around and stop it completely where steam is concerned.
Gauging is only one aspect of an entire systems engineering approach, after all.
I believe overall passenger injuries are down, but everything has disadvantages as well as advantages, and of course its sensible to address the disadvantages.
There’s rolling stock policy? Stadler are delivering FLIRTs with low floors, Hitachi are delivering 8xx with high floors to allow space underneath for engines. Hitachi are 26m long, FLIRTs 16 or 21 and have articulation.
Reverse that and you find NR setting parameters around what exists, with manufacturers saying “this isn’t compatible with our FLIRT/AT etc rolling stock platform and we’d have to bespoke it (more), and it will take longer/ increase the price”. East Midlands’ Hitachi 802 > 810 redesign means that what would have been a straightforward follow on order is taking 4 years to reach service
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(In practical use and you have a loco boiler to run an ejector from, vacuum is a better brake than Westinghouse - handier and more reliable, therefore safer - this can be mitigated with two pipes along the train but that was never general in steam days.
Vacuum brakes were used in the USA on the three foot gauge and the elevated railroads - both with little through running with other railways and the latter with lots of stops. Also extensively used at the same time on the Continent.)
All the cladding has been removed and some work has been done inside the boiler. It has had an inspection and "50 copper side stays together with lots of foundation ring and other steel rivets" will need replacing (according to Main Line #190). As it is the locomotives 100th birthday in 2025(24?) I'm sure it will be finished well before then.
Work continues inside the boiler with replacing of rivets and side stays. Not an easy job with an oxy/fuel (Acetylene or Propane?) torch inside the firebox!
Only just noticed this - not paying attention at the back!
Superficially, vacuum is a simpler and therefore better brake. (It was certainly claimed to use less steam than Westinghouse.)
But as the railways have developed vacuum's limitations became more obvious. Firstly, it is less effective at the end of a long train (problem for US standard gauge lines). Second, its pressure differential of 10 lb/in² against atmosphere at sea level makes it very unattractive in the mountains (Alps, Rockies, Andes, &c.). Thirdly, it is very much less capable for applying brake force in proportion to loaded weight. The latter is less of a problem on a passenger system, but a big deal in freight. It was a bit of luck for AB-equipped lines that changing from steam to diesel or electric was relatively easy - after all the locos needed compressors for air supply on the loco anyway.
I beg to differ on one small point. Phillipson (Steam locomotive design: data and formulae) estimated that a vacuum ejector used three times as much steam as an air pump in comparable applications. This isn't particularly surprising; although a vacuum ejector has the virtue of great mechanical simplicity with very few moving parts, creating vacuum tends to be fairly inefficient compared to compressing air, and the small ejector runs constantly.
In 'Swindon Steam' Ken Cook (ex WR and LNE CMWE in BR days) states that a committee was set up at the grouping to decide on whether to standardise on Westinghouse or vacuum, and that the Westinghouse used appreciably less steam, although the GWR setup with vacuum pump rather than small ejector ran it fairly close.
I wish I could recall where I saw the bit about steam consumption.
In Don Bradley's 'LSWR Locomotives: The Adams Classes' he quotes results of trials with both Automatic Vacuum and Westinghouse brakes. 2 engines each were fitted with the brakes:
The 2 with AV worked a total of 3,685 miles between them "Effective, reliable, simple operation, £4 6s 10d maintenance, no failures".
The 2 with Westinghouse brake worked a total of 4,490 miles between them "Strong and rapid acting, £21 6s 5d maintenance, three failures with burst pipes, two with defective pumps".
Not hard to see how a Victorian railway plumped for vacuum! Still a shame , taking the long view, though.
Would posts #53 to #56 be better in the Mutual Improvement section?
Webb on the LNWR also ran trials between trains equipped with the automatic vacuum and air brakes (and, like Adams, with the simple vacuum brake as well) and got the same answer in that the air brake was more expensive to maintain and suffered a number of failures. Note, however, that neither of these engineers commented on the performance of the brake itself, whereas Stroudley on the Brighton stated that he chose the air brake because it gave the best performance during the Newark brake trials.
In that light, I’ve always found it interesting that of the three companies around London who standardised on air brakes, all three had very intensive suburban passenger traffic. (LBSCR, LCDR, GER). In the LCDR case at least, they evidently found the benefits outweighed the additional licensing costs, despite their general status as a somewhat impecunious company.
Ditto the Isle of Wight's pre-grouping lines (partially excepting the FYNR, who managed to use both systems!).
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