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Post by George in Brussels on Jul 15, 2005 20:24:58 GMT
Hello everyone - having been reading so many fascinating threads for a while (for which, many thanks), I thought I would ask a question. Apologies if I'm in the wrong place.
What I was wondering is how and when you use the differing motoring position on your controller. I know that in pre-1992 trains you have three positions, shunt, series and parallel (I think), but when do you use. E.g. do you move gradually through them at different speeds as you accelerate or do you move straight to the fastest or what do you do?
Please excuse my ignorance, but would most grateful for your explanations. Thanks!
PS I'm a Londoner living in Brussels and the customer service on the tube is a million times better.
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Deleted
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Post by Deleted on Jul 15, 2005 20:32:00 GMT
on 92 stock, and 95/96's, the motoring and braking is all on one 'handle' a 'CTBC' or Combined Traction Brake Controller. Its a fore - aft controller; the further forward you push the faster you will reach full speed, further back you pull, the quicker you slow down; releasing the 'deadman' which is a 'swivelling arm' on the CTBC will apply full emergency braking. There is a 'mid point' on the controller, like a notch, which is where there is no brake and no power, a 'coasting notch' so to speak. On the Central Line, which uses the 92's, it's mostly Automatic Operation now. But I know from experience that, to some Drivers, there are two controller positions; full power, or full brake... ;D
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Post by Bill on Jul 15, 2005 22:48:51 GMT
on the Bakerloo (72 stock) most drivers tend to just bang the TBC straight into parallel. However the "official" way is to momentarily shift the tbc into shunt and then whack it round into parallel. this of course works fine unless you are driving one of about half the fleet with weak door interlocks, in which case (depending on the severity of the defect) you have to stay in shunt, moving slowly through series and then into parallel.
you can also select the rate of acceleration: this helps with weak door interlocks and driving in the rain. rate 1 being painfully slow and rate 2 being normal, if you have a 1972 mkII then the rate selecter is on the control barrel, if you have a 1972mkI its above your head on the pillar near the deicing switch, which is a pain in the rear to keep reaching up to mess about with! of course every train in the fleet is slightly different so you just have to play it by ear when you pick up.
I'm told the C stock is a very similar setup to the 72's. Some of you District/H&C drivers might be able to elaborate further... ;D
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Post by Bill on Jul 15, 2005 22:50:49 GMT
sorry just re-read the above post: mkI trains have the rate selecter on the barrel and mkII's have it on the pillar. I'm half asleep!!
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Post by Deleted on Jul 16, 2005 1:53:50 GMT
On District line (C and D stocks) I normally stick it straight into parallel unless there is a big rail gap just after the platform (as that would cause the motors to drop out with a bang) or the train has dodgy door interlocks (loss of pilot light when leaving a station in parallel).
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Post by q8 on Jul 16, 2005 8:24:50 GMT
With the pre "one arm bandit" type of controller you generally wound up straight to full parallel. There was a rate switch on the reverser key barrel on "Q" and "R" stock and a domestic light type dome switch on "COP" stocks. However if you were quick with your hand you could "hand notch" with a BTH type controller.
Once in top notch you generally leaned against the back cab wall with the handle in the series position
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Post by George in Brussels on Jul 16, 2005 8:25:58 GMT
Thanks for the answers, folks. So when would you use "series" then? Or wouldn't you? On a typical run between stations (assuming you don't get stopped at a signal), would you keep the TBC in parallel all the time until you needed to start braking or is it more complicated than that? Thanks again for humouring me!
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Phil
In memoriam
RIP 23-Oct-2018
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Post by Phil on Jul 16, 2005 8:37:35 GMT
And now another (supplementary) question. how, or why, do dodgy door interlocks affect going straight to parallel?
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Post by Bill on Jul 16, 2005 8:51:05 GMT
This is where it gets more complicated... If you were in a lower speed area - ie going over points, into sidings, etc, you don't want to go straight into parallel as shutting off the motors when you reach say 10mph will cause the train to throw itself about a bit. similar to when a driver loses his pilot light when pulling away. so you would use series to reach the desired speed and then shut off for a smoother ride.
You would tend not to leave the tbc in parralel all the way between stations as you would shut off (off and release) and coast once youve reached the desired line speed. Occasionally motoring up again to maintain speed, especially on gradients and curves. Again, this is where you may elect to use series rather than parallel.
Certain places may require a use of a driving skill known as "series notching", which involves momentarily winding up to series, waiting for the motors to engage and knocking the tbc round a notch down to shunt without returning to off and release. this has the effect of giving you a smoother ride and being able to maintain desired speed and is especially useful for going up gradients. The steep incline into London Road depot on the Bakerloo is a prime example. The reason being is something to do with knocking out the RPA or something. I'm not an IO! Can anyone elaborate?
You can also do this notching exercise between Parallel and Series, but the noticeable effects are minimum. I only realised it had any effect when many moons ago I had a mainline burst on the rear unit and had to get my train empty all the way into stonebridge depot with half motors, SAPB's hanging on, random things happening that all the stock training in the world won't prepare you for, like pass alarms, and train secure lights á la Q8's story in the historical thread! ;D
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Post by Bill on Jul 16, 2005 8:55:55 GMT
And now another (supplementary) question. how, or why, do dodgy door interlocks affect going straight to parallel? The sudden jerk of the train causes the weak doors closed circuit to break, causing you to lose your pilot light and motors to drop out (loud pop and a jolt passengers often experience) you have to re-stroke the tbc to regain your pilot light and thus continue motoring. If you accelerate more slowly it has the effect of not breaking the circuit and thus you keep your pilot light and motors and everyone's ride is smoother. i believe it is to do with the mercury in the door interlocks. again, my knowledge of train equipment stretches to about enough to get out of a defect, but not enough to explain the whys and wherefores of a lot of things! someone else can probably elaborate.
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Post by George in Brussels on Jul 16, 2005 9:05:51 GMT
I see - so am I right in thinking that the top speed in parallel is higher than in series and the rate of acceleration to that top speed is also higher?
Another (related) question: I was travelling from Camden Town to Euston a few years ago (at the time Mornington Crescent was shut) on a 1959 stock train (fabulous hissing and clicking as they accelerated!), but on this occasion we made the entire journey at what couldn't have been more than 10mph and with the motors running the whole time. I guessed the driver had the controller in shunt the whole time. By the time we got to near Euston, smoke had started to enter the car and someone activated the passenger alarm. When I got to Euston, I got off PDQ and noticed that there was a red glow coming from underneath the train (the resistances, I guess). My question, although I'm not sure anyone will know, is why on earth did the driver go all the way from Camden Town to Euston in shunt?
Thanks, Bill by the way!
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solidbond
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Post by solidbond on Jul 16, 2005 9:08:20 GMT
This is where it gets more complicated... If you were in a lower speed area - ie going over points, into sidings, etc, you don't want to go straight into parallel as shutting off the motors when you reach say 10mph will cause the train to throw itself about a bit. similar to when a driver loses his pilot light when pulling away. so you would use series to reach the desired speed and then shut off for a smoother ride. You would tend not to leave the tbc in parralel all the way between stations as you would shut off (off and release) and coast once youve reached the desired line speed. Occasionally motoring up again to maintain speed, especially on gradients and curves. Again, this is where you may elect to use series rather than parallel. Certain places may require a use of a driving skill known as "series notching", which involves momentarily winding up to series, waiting for the motors to engage and knocking the tbc round a notch down to shunt without returning to off and release. this has the effect of giving you a smoother ride and being able to maintain desired speed and is especially useful for going up gradients. The steep incline into London Road depot on the Bakerloo is a prime example. The reason being is something to do with knocking out the RPA or something. I'm not an IO! Can anyone elaborate? You can also do this notching exercise between Parallel and Series, but the noticeable effects are minimum. I only realised it had any effect when many moons ago I had a mainline burst on the rear unit and had to get my train empty all the way into stonebridge depot with half motors, SAPB's hanging on, random things happening that all the stock training in the world won't prepare you for, like pass alarms, and train secure lights á la Q8's story in the historical thread! ;D You obviously need better stock trainers then ;D ;D I ALWAYS tell trainees on C stock training about the possibility of complications caused by Main Line Bursts on the rear unit. Amongst these, as you say, are the Passenger Alarm sounding, also loss of pilot light, or both The reason for this is simply, with no main line air there are no motors on the rear unit to push it forward, there are the Spring Applied Parking Brakes on, dragging it back, and because there is no air on the wedges on the coupler, the studs on the coupler sometimes come apart, breaking the contacts ;D
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Post by Bill on Jul 16, 2005 9:15:57 GMT
Top man! Although i dont think it's the stock trainers, more my selcetive memory and general forgetfulness! Now, if C stocks are made up of 3 units rather than the conventional 2. how does that affect you when dealing with defects like bursts? ;D
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Post by Deleted on Jul 16, 2005 9:22:32 GMT
Is there a general problem with the doors on 67/72ts?
When I was using the Vic every day, the motors would often drop out as we pulled away from a station, this doesn't seem to have changed post-refurb either.
I remember a Northern Line driver telling me that the MK 1 72TS was prone to door trouble; getting the pilot light at stations on a severe curve.
Thanks
/Dave
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Post by Bill on Jul 16, 2005 9:33:44 GMT
MkI's have much heavier doors than MkII's which is apparently the cause of the problem. I still prefer to drive MkI's though. However, you tend to only get one unit as it will generally be coupled to a MkII. Very rarely you get a full train with both units MkI.
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Post by q8 on Jul 16, 2005 11:30:15 GMT
I was told a long time ago that the reason you got motor drop-out on "C" stocks, especially in rate two is that the back EMF detector on the acclerating relays is set too low amp wise. I am informed that if it were set at a slightly higher amperage before the next step then the motor drop out would be far less.
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Post by russe on Jul 16, 2005 23:17:37 GMT
For a 6-car train (say), can anyone put a figure (metres/sec, or imperial) on what a typical acceleration would be? Say level track and dry conditions.
Russ
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Post by q8 on Jul 17, 2005 0:49:43 GMT
For a 6-car train (say), can anyone put a figure (metres/sec, or imperial) on what a typical acceleration would be? Say level track and dry conditions. ------------------------------------------------------------------------
Generally about 1mph per second Up to 30mph then a bit less.
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Post by chris on Jul 17, 2005 11:17:42 GMT
Work it out: Acceleration = Change in velocity/time taken
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Post by q8 on Jul 17, 2005 13:21:33 GMT
Work it out: Acceleration = Change in velocity/time taken] ------------------------------------------------------------------------
Did that in the 1970's with a stopwatch results follow. 0 to 30mph =
"R" stock 23 seconds "1956/59/62 stock" 30 seconds "A" stock (with flag down) 27 seconds "C" stock 25 seconds 1967/72 stock 25 seconds
Only stocks with a clock speedo tested.
Stock with best deceleration "R" Stock with slowest RPA 1956/59/62. Stock fastest notching up "R"
Fastest stock other than "A" "C" closely followed by "R"
Most powerful horsepower "Q" Stock with best brake "Q" and "standard" (A type EP Brake) Stock with best self lapping brake "1938"
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Post by Deleted on Jul 17, 2005 14:26:36 GMT
"1956/59/62 stock" 30 seconds 1956 stock defiantly had slower acceleration than 1959 stock, on the Northern line trains weren't made up of two 56 stock units, a 56 stock unit always had a 59 unit at the other end, even then it always felt like you had a motor out.
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Post by Deleted on Jul 17, 2005 17:18:20 GMT
had a duff train once, with motor probs. Train really dragged going up that slog from Mile End into Stratford.
When we had the last Steam on The Met [in 2000], was chucking it down with rain and allsorts. Left Pinner, and heard the wheels pick up. going about walking pace, driver just left the handle wide open. After about a minute, I think he either shut off or they tripped out. There was a distinct smell hanging around the car, and clouds of smoke drifting back along the train...
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