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Post by Deleted on Sept 2, 2014 17:20:04 GMT
One of the things that I've always been interested in is how LU drivers are taught to apply power and brakes.
Now, I know it'd be asking a bit much to just say - how do you drive a tube train - and obviously traction knowledge is entirely dependent on stock and there's a lot to it.
Instead I'd just like to restrict myself to braking technique. How are drivers taught to stop; what is the ideal braking technique when coming into a station? So do you aim to brake hard at first, then gradually reduce braking effort? Do you apply the brakes gradually, have a sort of peak right in the middle, and then ease them off? Do you aim to keep the braking effort constant as much as possible? Is it best to stop with as little braking effort as possible (for the gentlest stop), or the same amount that you've been using for the past few seconds (so that it doesn't jerk around too much)? Is it best to have little spurts of braking, or is it ideal if you can avoid taking the brakes off (so that it doesn't jerk around too much)? Is there any limit (obviously apart from the speed limit) on how fast you should approach a platform?
Also, how big an effect does the weight and weather have? I mean, I would imagine it's quite big, but can you usually get away with braking in more or less the same place, but adjusting how you brake, or would you have a marker for dry conditions and one for wet conditions, or would it really vary with how the train ifeels?
I know I'm asking a lot and I know it would depend on the train in question, but really I just want the style of stop you aim for in your own minds. Whether you favour the gradual easing off of the brakes, or the constant braking, whether you prefer to have little stabs of brakes, etc. etc.
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Colin
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Post by Colin on Sept 2, 2014 18:00:21 GMT
If you drive a car you'd be able to answer you're own question as the basic principles are no different - the slower you go the less braking effort you need. If it's raining or foggy, you allow more time & distance for braking.
There's no hard and fast precise brake point for each platform as each train varies in how it performs. Not only that but gradients, curves, actual speed and loading all add to the variances. Even temperature can make a difference. It really comes down to having a feel for what is required in order to stop in the right place.
As an instructor I can give guidance on roughly where would be a good point to start braking, and I can offer guidance as to which position the TBC ought to be in, but it really comes down to how the train responds.
Now you mentioned weather which obviously has a major effect out in the open as each metal wheel only has about a quarter of an inch square in contact with the metal rails. As I mentioned above, if its raining we just allow more distance in which to brake and if necessary use lighter brake applications to avoid locking up & skidding. Modern stocks have systems such as wheel slide protection which help out in wet conditions which in simple terms is like ABS in a car.
The bottom line is that the train must be under control when it enters a platform - that is what all LU drivers are taught.
EDIT:
As for whether we prefer to keep the braking smooth........we operate a passenger train service........the answer therefore ought to be self explanatory!
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hobbayne
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Post by hobbayne on Sept 2, 2014 20:33:15 GMT
And we will soon be in the leaf fall season where every good train operator earns his/her money. Even the ATO lines suffer from low rail adhesion. I remember last year the railhead was so very slippery I took it out of ATO at Buckhurst Hill and drove in manually to Leyton.
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Post by 1018509 on Sept 4, 2014 15:36:53 GMT
As I've said on here before; any damn fool can drive a train but stopping it in the right place is where the skill comes in
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Post by John Tuthill on Sept 4, 2014 17:12:26 GMT
As I've said on here before; any damn fool can drive a train but stopping it in the right place is where the skill comes in Remember years ago whilst working on a RAF base, there was a notice above a standby generator which said: "Before you start it make sure you know how to stop it" Could apply to ANY piece of machinery  |
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rincew1nd
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Post by rincew1nd on Sept 4, 2014 17:19:41 GMT
Quite, I'm more than happy to drive our steam roller along river valleys and uphill, but downhill is what gives me the willies. Especially as the last time I drove down a hill, having stopped to change into bottom gear, wound the hand-brake on, centred the reverse and applied the trailer brake I then controlled the speed nudging the reverser backwards; I looked down to see one of the wheels not rotating with quite a lot of hill left to go! Luckily it only slipped a couple of inches, however with ten tons of engine and 3/4 of a ton of coal in the trailer pushing it down the ill it felt like an eternity! When it happened again five yards further on I reached out the back of the footplate pdq and heaved on the trailer brake another few clicks which did the trick - thank goodness. Next year, we've decided that the extra two minutes of an alternative route is worth it for the minute changing into bottom and the minute changing back into top!
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Post by tubelightonline on Sept 4, 2014 20:00:56 GMT
Didn't the late, great Fred Dibnah once accidentally plough one of his steamrollers into a wall somewhere? Suffice to say, the wall came off worst! Just goes to show that it can happen to the best of them!
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roythebus
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Post by roythebus on Sept 5, 2014 7:43:40 GMT
Braking technique have changed over the years as the braking systems have changed. I learnt with the A type EP brake fitted to Q stock, the D type EP brake fitted to everything else at the time, the rheo brake fitted to C69; then on BR the vacuum brake, single and twin pipe air brake, straight Westinghouse, unbraked freight, now THAT took some getting used to; then later the awful disc brakes and the like fitted to 508s, then 455 disc brakes which were never much good at stopping where you wanted them to.
So I've driven most thing from the humble diesel shunter through to express passenger at 100mph plus. Yes, every one needs a different technique. The SR teaching used to be "leave the braking till the last minute", especially with the Westinghouse as you only have 3 application with that, brake hard, then stop with the brake releasing.
The advent of the 508s put paid to that technique. Brake at Putney to stop at Barnes (if you're lucky) was the adage there.
Thee days I understand drivers are taught defensive braking, run in slow to avoid the risk of passing the signal at danger; this costs valuable time and sometimes negates the benefits of improved acceleration of modern stock. In my opinion the wheel slide protection systems are nowhere as good as they are made out to be. The "seat of the pants" method used on the old stock was far better and cheaper.
Every location is different, be it in a tunnel or an open section, that is why the driver has to have route knowledge. There's little room for mistakes.
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Ben
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Post by Ben on Sept 5, 2014 12:51:47 GMT
It'll be defensive driving that'll ultimately be the downfall of manual control on the busier tracks...
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Post by Deleted on Sept 5, 2014 21:49:01 GMT
So I've driven most thing from the humble diesel shunter through to express passenger at 100mph plus. Yes, every one needs a different technique. The SR teaching used to be "leave the braking till the last minute", especially with the Westinghouse as you only have 3 application with that, brake hard, then stop with the brake releasing. The advent of the 508s put paid to that technique. Brake at Putney to stop at Barnes (if you're lucky) was the adage there. Thee days I understand drivers are taught defensive braking, run in slow to avoid the risk of passing the signal at danger; this costs valuable time and sometimes negates the benefits of improved acceleration of modern stock. In my opinion the wheel slide protection systems are nowhere as good as they are made out to be. The "seat of the pants" method used on the old stock was far better and cheaper. Tokyo's incredibly busy mainline commuter network in and around the city operated by JR is all manually driven and also conventionally manned with a Guard on every train, alot of these lines are just as, if not more frequent than the Victoria line (and a hell of alot more punctual than anything in London) yet they are just as safe. These trains rather than the measly 3 steps with disc brake only trains we have here, they have 8 service braking steps and are equipped with axle mounted discs and also tread brakes on the same bogie. They drive how you've described drivers here used to be taught how to drive on stopping services and it works perfectly! It is annoying when you hear and read in magazines from supposed experts, that manual driving for a 24tph service on Thameslink would be 'impossible' when it clearly is possible! |
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roythebus
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Post by roythebus on Sept 6, 2014 8:37:21 GMT
Quite! The W&C managed in excess of 20tph when it had the proper stock with Westinghouse brakes. It is the inability of the paperwork and the design of brakes to do what they ought to do that prevents a lot of things here. That's progress.
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Post by Deleted on Sept 6, 2014 14:46:00 GMT
Clicky Just to illustrate what I mean about fast approaches! And train frequencies on the equivalent of the Circle line.
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Post by domh245 on Sept 6, 2014 15:39:55 GMT
Its quite impressive that they have such high frequencies but with 40 second long dwell times! I do somewhat expect that their signalling is much advanced that even the 4 aspect signalling on NR and much more that the equivalent 3 aspect system on LU - I understand that this line has in-cab signalling. I suspect that the main reason that they can get away with manual driving still is because the drivers are trained to very high standards - that is not to say that drivers in britain aren't, it is more that the Japanese train drivers are trained so much more (800 hours or so) and the standards are unbelievably high - stopping with 10cm accuracy etc.
When you look at it though, from the first train starting to leave to the next one arriving, there is a gap of 75 seconds, and in the course of that almost 9 minute video, there are 4 trains, which you can often see on the SSL during the peaks - Just saying...
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Post by Deleted on Sept 6, 2014 15:48:32 GMT
I do somewhat expect that their signalling is much advanced that even the 4 aspect signalling on NR and much more that the equivalent 3 aspect system on LU - I understand that this line has in-cab signalling. Hmmm one thing that is often completely left out in these debates is that it really wouldn't be difficult to design a vaguely sophisticated ATP system for manual driving, if there were the will to do so. The debate is almost always presented as a dichotomy: either you have shiny new ATO, or you have legacy signalling. When you look at it though, from the first train starting to leave to the next one arriving, there is a gap of 75 seconds, and in the course of that almost 9 minute video, there are 4 trains, which you can often see on the SSL during the peaks - Just saying... Quite. |
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Post by Indefatigable on Sept 6, 2014 15:55:01 GMT
If I might chip in a little, the Tokyo metro does not have "One Under"s or Suicides - I understand them to be called "Human Interventions"
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Post by domh245 on Sept 6, 2014 16:02:16 GMT
They do have "human interventions" and just to give an idea of how obsessive the Japanese Railways are with punctuality, when such an event occurs, the family of the person involved will often end up (partialy) footing the bill for the delay
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Post by Deleted on Sept 6, 2014 16:12:31 GMT
Its quite impressive that they have such high frequencies but with 40 second long dwell times! I do somewhat expect that their signalling is much advanced that even the 4 aspect signalling on NR and much more that the equivalent 3 aspect system on LU - I understand that this line has in-cab signalling. I suspect that the main reason that they can get away with manual driving still is because the drivers are trained to very high standards - that is not to say that drivers in britain aren't, it is more that the Japanese train drivers are trained so much more (800 hours or so) and the standards are unbelievably high - stopping with 10cm accuracy etc. When you look at it though, from the first train starting to leave to the next one arriving, there is a gap of 75 seconds, and in the course of that almost 9 minute video, there are 4 trains, which you can often see on the SSL during the peaks - Just saying... Yes, in cab signalling similar to Central line ATP with target speeds changing depending on how close behind the following train you are etc, it's called D-ATC, which is an in house system developed from the original system used when the Shinkansen first opened. Conventionally signalled lines in Tokyo use ATS-P which is very similar to the NR 4 aspect signalling but with 5 aspects. It has ATP on top of that to stop trains passing red signals also. 11 coaches with entry points to the platforms at multiple locations is why the dwell times are that long, I was comparing it more with for example London Bridge where some dwell times are 2 minutes! |
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rincew1nd
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Post by rincew1nd on Sept 6, 2014 17:39:25 GMT
When you look at it though, from the first train starting to leave to the next one arriving, there is a gap of 75 seconds, and in the course of that almost 9 minute video, there are 4 trains, which you can often see on the SSL during the peaks - Just saying... The start-stop interval in the second video does seem similar to what I remember of the Victoria Line at the moment, but with a much longer dwell time. It seems the train length is greater though, so perhaps that's how a capacity increase is brought about? |
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Post by metrailway on Sept 6, 2014 17:40:49 GMT
The problem on the main line is that there is the requirement for overlaps of at least 200 yards beyond a colour light signal. There is the scope for reduced overlaps on NR for sections where speeds are low but the overlaps are still rather long. At 30mph the minimum overlap would have to be 70m. This would cut the theoretical max capacity on Thameslink.
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Colin
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Post by Colin on Sept 6, 2014 21:39:57 GMT
These trains rather than the measly 3 steps with disc brake only trains we have here, they have 8 service braking steps and are equipped with axle mounted discs and also tread brakes on the same bogie. LU brakes are far more superior to whats found on the NR network - D stock for example has a 7 step air brake [steps are used in various combinations] on wheel treads along with rheostatic braking. S stock has air on treads along with Rheostatic and regenerative systems plus wheel slide protection. Other stocks are equally equipped. If I might chip in a little, the Tokyo metro does not have "One Under"s or Suicides - I understand them to be called "Human Interventions" LU doesn't do person under train anymore - they're now "person on the track".
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Post by Deleted on Sept 6, 2014 21:52:51 GMT
LU doesn't do person under train anymore - they're now "person on the track". You wouldn't happen to know why that is would you? |
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hobbayne
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Post by hobbayne on Sept 7, 2014 12:05:42 GMT
LU doesn't do person under train anymore - they're now "person on the track". You wouldn't happen to know why that is would you? Its part of LUL's dumbing down of information, and being careful with the info that passengers actually need. Also, appaearing to be 'Proactive' about dealing with issues so it looks as they are actually doing something about it. Hence the "While we fix a signal failure at ...." |
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Post by Indefatigable on Sept 7, 2014 12:16:05 GMT
You wouldn't happen to know why that is would you? Its part of LUL's dumbing down of information, and being careful with the info that passengers actually need. Also, appaearing to be 'Proactive' about dealing with issues so it looks as they are actually doing something about it. Hence the "While we fix a signal failure at ...." Would that also include something "trespasser on the line"? Just that I was held at Sloane Square on a District Line after the doors had closed. After about ten to twenty seconds of not moving, the driver came on and said there was a trespasser on the line in front of us. Took a minute or so to get moving as I recall |
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Post by Deleted on Sept 7, 2014 12:18:18 GMT
LU doesn't do person under train anymore - they're now "person on the track". You wouldn't happen to know why that is would you? It's something that the Samaritans recommended to LUL. |
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Post by Tomcakes on Sept 7, 2014 17:02:39 GMT
You wouldn't happen to know why that is would you? Its part of LUL's dumbing down of information, and being careful with the info that passengers actually need. Also, appaearing to be 'Proactive' about dealing with issues so it looks as they are actually doing something about it. Hence the "While we fix a signal failure at ...." Also noticed that the Northern line is "Part Closed" this weekend rather than "Part Suspended"... does that sound better? If taken to extermis it could be argued that passengers need not really know why the delay has occurred, they need only know what the effects are. On the other hand, it is a little more 'human' I suppose to hear a reason for the delay, even if it becomes regarded as a pithy excuse. (I once overheard station staff retrieving a passenger's book which they had dropped on the track at a station - "Now that really is a case of leaves on the line!"). |
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Post by superteacher on Sept 7, 2014 17:28:29 GMT
"Part suspended" is usually used for unplanned service suspensions with "Part closed" reserved for planned works.
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class411
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Post by class411 on Sept 7, 2014 17:58:50 GMT
[ If taken to extermis it could be argued that passengers need not really know why the delay has occurred, they need only know what the effects are. On the other hand, it is a little more 'human' I suppose to hear a reason for the delay, even if it becomes regarded as a pithy excuse. Isn't that what they often do already? Many times I hear "We are being held at a red signal". No Sh*t, Sherlock! And there was me thinking we'd stopped so that the driver could admire a particular piece of tunnel wall of he was fond. |
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roythebus
Pleased to say the restoration of BEA coach MLL738 is as complete as it can be, now restoring MLL721
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Post by roythebus on Sept 7, 2014 18:39:10 GMT
The old W&C stock could be stopped with an accuracy of 10cm, and that was with the Westinghouse brake. When filming an issue of Dempsey and Makepiece, I was the driver, and was asked by the film director could I stop by this line (the stop mark). Yes, which side of the line was my reply. I managed to stop dead on the approach side of the line, and the next run in on the far side of the line!
Another party piece was to stop during service hours such that the coupler plate would bounce forward at Bank and kiss the buffer stop, leaving a greasy mark, without tripping the "train hit buffers" treadle. The signalman there never did find out whodunnit! Now that is accurate stopping.
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Deleted
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Post by Deleted on Sept 7, 2014 18:40:36 GMT
[ If taken to extermis it could be argued that passengers need not really know why the delay has occurred, they need only know what the effects are. On the other hand, it is a little more 'human' I suppose to hear a reason for the delay, even if it becomes regarded as a pithy excuse. Isn't that what they often do already? Many times I hear "We are being held at a red signal". No Sh*t, Sherlock! And there was me thinking we'd stopped so that the driver could admire a particular piece of tunnel wall of he was fond. I always enjoy being told we're being held at a red signal on the Central line when, in fact, we're sitting it a block maker board. Amounts to the same thing, of course, 0/0 code and 'red signal' makes much more sense to the punters, of course, but still, the only thing red about BMBs is the stripe, which is always there...Not too important, but I can't help it  |
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Deleted
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Post by Deleted on Sept 7, 2014 18:54:18 GMT
These trains rather than the measly 3 steps with disc brake only trains we have here, they have 8 service braking steps and are equipped with axle mounted discs and also tread brakes on the same bogie. LU brakes are far more superior to whats found on the NR network - D stock for example has a 7 step air brake [steps are used in various combinations] on wheel treads along with rheostatic braking. S stock has air on treads along with Rheostatic and regenerative systems plus wheel slide protection. Other stocks are equally equipped. If I might chip in a little, the Tokyo metro does not have "One Under"s or Suicides - I understand them to be called "Human Interventions" LU doesn't do person under train anymore - they're now "person on the track". Sorry if it wernt clear! I was talking about current mainline stock that roythebus was talking about such as Class 508s. |
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