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Post by trc666 on May 4, 2015 18:26:31 GMT
Evening, sorry for the long absence but I have a question!
I'm writing a timetable for Wembley Suburban Simsig and want to input defensive driving rules into the timetable. Is anybody able to get hold of the defensive driving policies for London Overground and Underground (particularly for the Bakerloo line)?
Thanks in advance to anyone who can help.
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Post by superteacher on May 4, 2015 19:59:23 GMT
Also known as slow driving.
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class411
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Post by class411 on May 5, 2015 7:44:04 GMT
Also known as slow driving. Indeed. (Or, on occasion, slightly faster if you wish to avoid getting gapped!) There are many things you can do in a road vehicle apart from choice of speed - e.g. Lane usage, indications, gap maintenance - but these are either not applicable of decided by someone else, on a railway. I'd be interested to know if there is anything a train driver can do apart from speed selection (even smooth stopping is, presumably a matter of getting the speeds correct on approach). |
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rincew1nd
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Post by rincew1nd on May 5, 2015 11:46:06 GMT
I gather part of mainline defensive driving includes aiming to stop a loco length before the signal, rather than up against it. On the WCML a lot of SPTs are now individually mounted 20' in the rear of the signal, with little walkways.
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class411
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Post by class411 on May 5, 2015 12:05:49 GMT
I gather part of mainline defensive driving includes aiming to stop a loco length before the signal, rather than up against it. On the WCML a lot of SPTs are now individually mounted 20' in the rear of the signal, with little walkways. Given what you said in your first sentence, would they not be be better mounted 20' in front? (Assuming an 'SPT' is some kind of telephone.) |
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Post by tjw on May 5, 2015 12:28:57 GMT
I gather part of mainline defensive driving includes aiming to stop a loco length before the signal, rather than up against it. On the WCML a lot of SPTs are now individually mounted 20' in the rear of the signal, with little walkways. Given what you said in your first sentence, would they not be be better mounted 20' in front? (Assuming an 'SPT' is some kind of telephone.) In the "rear" of a signal and "mounted 20' in front?" describe the same thing. Description below from Wikipedia, N.B. I can't be bothered to dig out my BR rule book and find the relevant section which may have a better explanation. "Signals are sometimes said to "protect" the points/switches, section of track, etc. that they are ahead of. The term "ahead of" can be confusing, so official UK practice is to use the terms in rear of and in advance of. When a train is waiting at a signal it is "in rear of" that signal and the danger being protected by the signal is "in advance of" the train and signal." |
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Post by norbitonflyer on May 5, 2015 12:53:34 GMT
The term "ahead of" can be confusing, so official UK practice is to use the terms in rear of and in advance of. When a train is waiting at a signal it is "in rear of" that signal and the danger being protected by the signal is "in advance of" the train and signal." This used to confuse me too, until I realised that, in relation to a signal, "rear" and "advance" are defined in relation to the person observing it, not the notional "railway policeman" for which it is a substitute, who would be facing the oncoming train. It helps if you think of the signal as serving the same function as the tail light of a train - the light is projected to the rear of the signal. |
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class411
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Post by class411 on May 5, 2015 13:44:12 GMT
Yes, I can see it's not straightforward, and must rely on a convention rather than the simple rules of English, because, when you think about it (if you consider a signal is 'facing' the direction the light beam shines), what is 'in front' of the signal is in the opposite direction to what is 'in front' of the train!
So it seems to be that railway practice is to consistently use rear/advance with respect to the direction the train is pointing.
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Post by 100andthirty on May 5, 2015 15:01:01 GMT
Defensive driving isn't an exact thing as you will have seen from all the responses. However I hope the following helps.
I am comparing with what older drivers were taught to do and what ATO does. As you might well have experienced, ATO works on the principle that a braking rate for the stop concerned is pre-defined and the system works out roughly the closest to the stopping point that the brakes can be applied and still stop in the right place. This will be clearly seen on the Central and Victoria lines. Lower braking rates are always specified in the open rather because adhesion is more variable. The manual driving version might be crudely described as "enter the platform at 30MPH and slam on the anchors".
Defensive driving is much more along the lines of "if you know you've got to stop, get the speed off early and then go gently towards your stop mark (signal or stop board)".
I still recall my shock on a visit to Switzerland some years ago, but after UK adopted defensive driving, and seeing inter city trains speeding into terminal platforms just as if they were approaching a stop at a though station where the signal was green!
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Post by tjw on May 5, 2015 16:15:01 GMT
So it seems to be that railway practice is to consistently use rear/advance with respect to the direction the train is pointing. It is all very well for the Driver or Guard to talk about ahead and behind, Front or Back... but the Signalman on the other end of the SPT may have no idea what is ahead or behind the Driver / Guard. By using a consistent practice everyone should be able to understand the situation being reported. Note, I was passed out on the old BR rule book, I have no idea what the modern NR rulebook or LU rulebook uses. N.B. In the medical profession they do something similar with Left and Right, always the patients! not the doctor! |
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Post by tjw on May 5, 2015 16:24:21 GMT
I still recall my shock on a visit to Switzerland some years ago, but after UK adopted defensive driving, and seeing inter city trains speeding into terminal platforms just as if they were approaching a stop at a though station where the signal was green! I believe the Swiss railways have some sort of automatic train control similar to a tripcock but using electromagnets. The large electric locomotives also have some sort of electromagnetic braking. The brakes on Swiss trains seem very similar to the old Westinghouse brakes as used on the IOW steam railway... Very effective! I could find out more, a friend of my wife's is a Motorman / driver for the Swiss Railway. They also have a totally different safety regime! |
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Post by 100andthirty on May 5, 2015 16:36:07 GMT
tjw. I think you'll find that the "electromagnetic braking" you mention is rheostatic or regenerative braking. Magnetic braking - usually called magnetic track brakes - electromagnets mounted between the wheels of a bogie that attach themselves to the rails when energised - aren't used on Swiss railways as far as I've seen on their trains.
They do use magnetic track brakes on German high speed trains, and of course they are virtually standard on street running trams.
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rincew1nd
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Post by rincew1nd on May 5, 2015 17:58:40 GMT
Given what you said in your first sentence, would they not be be better mounted 20' in front? (Assuming an 'SPT' is some kind of telephone.) Others have outlined what is "in advance of" and "in the rear of", similar (but not necessarily the same) from "behind" and "in front of". An SPT is a Signal Post Telephone, which are now no longer on the signal post! |
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North End
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Post by North End on May 6, 2015 12:50:44 GMT
Given what you said in your first sentence, would they not be be better mounted 20' in front? (Assuming an 'SPT' is some kind of telephone.) Others have outlined what is "in advance of" and "in the rear of", similar (but not necessarily the same) from "behind" and "in front of". An SPT is a Signal Post Telephone, which are now no longer on the signal post! Bit of a bugbear of mine, but the terms 'in advance' and 'in the rear' seem to be slipping out of common use. I was recently asked by a controller to check for something "100 yards before the tunnel mouth". When I tried to clarify whether he meant in advance or in the rear, I was surprised to find he had no idea what I meant. The terms are there for a reason, namely that other language can introduce scope for confusion. I know it is, or certainly was, covered in training for this reason. |
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