my understanding is the dual control has a hand throw lever ... and a non dual control has a hand crank
thanks in advance..
can anyone give a good definition between "dual control points" and a "non dual control points"???
my understanding is the dual control has a hand throw lever ... and a non dual control has a hand crank
thanks in advance..
can anyone give a good definition between "dual control points" and a "non dual control points"???
my understanding is the dual control has a hand throw lever ... and a non dual control has a hand crank
thanks in advance..
The ESML box is located a minimum of say 40m from the switch machine, so that the operator cannot act too hastily. (See head-on collision on Trans line (Zanthus)).
See: https://en.wikipedia.org/wiki/Zanthus_train_collision
I cannot say whether such switch machines are described in NSW as "dual control" or "non dual control". Clearly a switch machine with an ESML are kind of dual control, but without using a throw over lever incorporated in the machine itself.
Maybe better terms would be:
Direct Dual Control: Hand throw handle incorporated in Switch Machine.
Indirect Dual Control: ESML handle stored say 40m from switch.
Non-dual control: No ability to operate points in an emergency.
The ESML Handle has a Kellogg Key welded on one endIsn't that an Annett key? That's what they look like to me, anyway.
Isn't that an Annett key? That's what they look like to me, anyway.
Kellogg keys (Milo G. Kellogg, founder of the Kellogg Switchboard & Supply Co., Chicago IL USA) are toggle switches found on telephone switchboards / concentrators and also on some early electric signalling panels for the control of signals, points and releases etc.
I forget how old EP (Electro-Pneumatic) could be controlled "by hand".
New installations have a "Fortress Lock", which allows push buttons to control the electric solenoids that operate the air cylinders. The main safety feature is a time release, so that after the necessary signal are put to stop, only after a wait of say 60 seconds can the points be moved.
When did the different kinds of power points and signals (air or electric) become available?
As far as I know, the first power signalling scheme in NSW was for Sydney Station, brought into use 13 March 1910, replacing a large mechanical box of over 100 levers. Photos of this original "Station Box" in action, the adjacent "Tunnel Box" and the mechanical boxes they replaced are not often seen.
Equipment was provided mainly by the McKenzie, Holland and Westinghouse Power Signal Co. Ltd. of Worcester, England, including electro-pneumatic two position lower quadrant semaphore signals, points and some track circuiting but no track circuit control of signals or points. There was no track circuit block or automatic signals; the absolute block system remained in use. The first automatic signalling (in Australia) was introduced in 1914 between Eveleigh Loco Jctn and Sydenham, consisting of two position lower quadrant home and distant semaphore arms. "Station Box" had a large McK, H & W miniature lever frame that was broken up and reused at (IIRC) Illawarra Junction, Sydenham and Petersham after its closure in 1924 (when Sydney Station West Signal Box - the one most people remember - was brought into use). Sydney Station East Signal Box was brought into use in 1916, also with a miniature lever frame. The large brick Station Box building was situated next to the Sydney Yard Controller's office and survived longer than the newer Sydney Station West.
I wonder how similar the original EP point mechanisms from Sydney Station were to the 1920s era NSWR Signal Branch designs which seem to remain in use throughout the old EP area.
The UK was considerably behind. The first main line use of power operation of points wasn't until 1899 - EP at Granary Junction (using US&S technology) and Crewe (the LNWR's own system of electric points operation).
The UK was behind when it came to implementing power signalling technology, but the story doesn't really end there, because the British were miles ahead when it came to actually using interlocking and the block system, a situation which essentially continues to this day.
The American railroads who have in more recent times simply switched off life expired power signalling systems without replacing them adopted a similar attitude.
The UK was behind when it came to implementing power signalling technology, but the story doesn't really end there, because the British were miles ahead when it came to actually using proper interlocking and the absolute block system, a situation which essentially continues to this day.
I would agree with you c1900. I wouldn't agree c1950, and I wouldn't agree that the UK is leading today.
the invention versus application comparison is an interesting one.
The American example demonstrates that power signalling technology does not necessarily mean higher safety integrity of the system overall.
Despite the great innovation of American signalling firms like GRS with NX route control, APB, CTC and ATP technology, the American railroad companies themselves were behind in terms of enforcing tight safety regimens bolstered by strong engineered controls. If the rules are rubbery or there is a heavy reliance on purely administrative controls to guard against human error, power equipment is no better than barbaric mechanical levers, rods and wires, and in fact it could be argued that it is worse due to its "deadly convenience".
It is rather ironic that the relatively primitive British manual block system had a better safety record than pre-APB/CTC American lines with automatic block signalling, but that is what happens when signals are relegated to the role of a guide, as an overlay on the pre-existing timetable and train order system that still forms the basis of American main line working.
The result of this stagnation in the UK and rapid development in the US was an evening out of the safety race. Shaw, in his book on US accidents, asserts that by WWII the accident rate in the US *per train mile* was equivalent to the UK. There were a large number of accidents, but this was because the US railway system was far bigger than any other system and had more trains. Any casual reading of the UK accident reports in the '50s will be struck by the number of serious accidents caused by block failures or misreading signals. This didn't really improve until the massive resignalling schemes really started to take their toll of traditional signalling - schemes that were largely based on US technology.
Such modern installations that were provided in the UK almost exclusively used technology that was developed in the US - to the extent that even today the standards for naming relays in the UK is recognisably based on the US scheme.
Could Historian supply a list of US abbreviations for signalling relays, please?
There is a big difference between inventing technology and using it, as Headshunt said...
In the UK the BoT essentially mandated in the 1890s a uniform level of signalling infrastructure over the entire country. There was *no* provision for varying the infrastructure depending on traffic. (There was subsequently some backing away from this position - light railways had lower infrastructure requirements. But these were never numerous in the UK.) This did provide a very safe railway, but at a price. Essentially the railway companies must have been wasting resources over signalling their branch and minor lines. These resources was then not available to be spent in other areas - such as improved signalling on their main lines.
I don't think that you've really understood my argument.
Essentially it is economic.
The US during the same period is a useful counterpoint. While you criticize the railways for the lack of uniformity and the manual processes, you fail to note that it was completely impossible for anything approaching a uniform signalling system to be used in the US. And certainly impossible for any technology to be uniformly adopted. The US had lines with far greater traffic than anything in the UK. Equally, they had huge mileages of line with, at best, one or two trains a day.
In the UK the BoT essentially mandated in the 1890s a uniform level of signalling infrastructure over the entire country. There was *no* provision for varying the infrastructure depending on traffic.
It wasn't just a matter of having a bad decade with the holes lines up. It was a consequence of lack of investment, and part of the problem must have been the deadweight of money spent on the less important lines.
Important lines got full automatic signalling with interlocking and (eventually) cab signalling. Minor branch lines had no signalling and the main line points were secured by switchstands. In the middle were vast mileages protected by automatic signalling superimposed over TT&TO working - because the major risk in this form of safeworking was rear end collisions.
Incidentally, I think that Australian railways were far better than the UK at adopting signalling systems that suited traffic levels.
I would agree - as I said in the previous posting - that the US managed safety poorly in the 19th century. But safety management improved greatly in the 20th. And this was done more efficiently than in the UK. Safety technology was applied where the risks were highest.
by the '50s, Shaw notes that the US railways were as safe as the UK railways per train mile
Incidentally, I think that Australian railways were far better than the UK at adopting signalling systems that suited traffic levels.
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