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Post by Deleted on May 27, 2014 17:19:00 GMT
As we were approaching Barbican westbound today, I noticed some heavy braking. My first thought was that we were slowing for the draw-up signal, until the T/Op acknowledged a handle down over the PA and said that he'd take the train into the platform before going back to investigate. So, my question is, when the Passenger Emergency Alarm (PEA) is activated on the S stock, does it apply the brakes automatically? The reason I ask is partly the heavy braking I noticed, and partly I remember hearing something about a button in the cab which is used when the PEA is activated and I'm sure something was said about it cancelling brake application, but I can't be sure, which is why I'm asking here, obviously.
Additionally, I know on the Central line, from reading the posters, that if a handle is pulled when some of the train is still in the platform (when pulling out) it will cause the T/Op to activate the brakes (that's what the old signs say on the 92s, I assume it has to be done manually? I know back in the old days they had exclamation marks marking the point before which brakes could still be applied, I think some are still around, nowadays I suppose they use the blue numbered plates counting cars out of the platform). But anyway, I was wondering if on the S stock the brakes come on (a) automatically and (b) everywhere, whether the train is in a station or not? Because this would seem unusual if it's so. Automatic braking makes a lot of sense, but I think most lines are like the central in that the train only comes into a halt if some of it is in a platform. It might be that the front of the train was in the platform at the time, I can't be sure, but I was in the first car and I think it was a few seconds before we left the tunnel. Either way I always imagined the brakes only came on in this way when the train was pulling out.
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Post by Deleted on May 27, 2014 19:58:49 GMT
On a related note, is the PEA connected up with the Signalling System on modern trains, so that the brakes apply automatically if the PEA is operated, if the signalling system detects any part of the train being within the "Platform Grounds" etc??
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Post by Dstock7080 on May 27, 2014 21:11:10 GMT
Additionally, I know on the Central line, from reading the posters, that if a handle is pulled when some of the train is still in the platform (when pulling out) it will cause the T/Op to activate the brakes (that's what the old signs say on the 92s, I assume it has to be done manually? I know back in the old days they had exclamation marks marking the point before which brakes could still be applied, I think some are still around, nowadays I suppose they use the blue numbered plates counting cars out of the platform). But anyway, I was wondering if on the S stock the brakes come on (a) automatically and (b) everywhere, whether the train is in a station or not? Because this would seem unusual if it's so. Automatic braking makes a lot of sense, but I think most lines are like the central in that the train only comes into a halt if some of it is in a platform. It might be that the front of the train was in the platform at the time, I can't be sure, but I was in the first car and I think it was a few seconds before we left the tunnel. Either way I always imagined the brakes only came on in this way when the train was pulling out. On the Central Line, as all other Line the emergency brakes are applied automatically when a passenger alarm is operated. Dependant on the trains' actual stopping position will determine if the Operators actions are to; proceed to the next station or deal with the alarm at the stopped location. On S Stock the same situation applies. On a related note, is the PEA connected up with the Signalling System on modern trains, so that the brakes apply automatically if the PEA is operated, if the signalling system detects any part of the train being within the "Platform Grounds" etc?? S Stock are linked to a track based detection system to verify the trains' position for the purpose of Selective Door Operation, PEA operation, platform CCTV viewing and sensitive edge operation. This system is a stand alone to the existing signalling. In the case of PEA operation, if the train is still within "station limits" (is the phrase used) the driver will be unable to override the emergency brake. |
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North End
Beneath Newington Causeway
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Post by North End on May 27, 2014 21:23:02 GMT
Additionally, I know on the Central line, from reading the posters, that if a handle is pulled when some of the train is still in the platform (when pulling out) it will cause the T/Op to activate the brakes (that's what the old signs say on the 92s, I assume it has to be done manually? I know back in the old days they had exclamation marks marking the point before which brakes could still be applied, I think some are still around, nowadays I suppose they use the blue numbered plates counting cars out of the platform). But anyway, I was wondering if on the S stock the brakes come on (a) automatically and (b) everywhere, whether the train is in a station or not? Because this would seem unusual if it's so. Automatic braking makes a lot of sense, but I think most lines are like the central in that the train only comes into a halt if some of it is in a platform. It might be that the front of the train was in the platform at the time, I can't be sure, but I was in the first car and I think it was a few seconds before we left the tunnel. Either way I always imagined the brakes only came on in this way when the train was pulling out. On the Central Line, as all other Line the emergency brakes are applied automatically when a passenger alarm is operated. Dependant on the trains' actual stopping position will determine if the Operators actions are to; proceed to the next station or deal with the alarm at the stopped location. On S Stock the same situation applies. On a related note, is the PEA connected up with the Signalling System on modern trains, so that the brakes apply automatically if the PEA is operated, if the signalling system detects any part of the train being within the "Platform Grounds" etc?? Not at all. btw, the phrase is "station limits". A couple of points of detail. On the 1995 stock as built there is a 'platform leaving timer', which from memory lasts for 16 seconds after selecting motoring. If the PEA sounds in this time, the brakes will apply, and the only way to move the train is to either cut out the PEA (sealed rotary switch behind the driver), or go back and reset the handle. If a PEA sounds beyond the 16 seconds, there is no effect on the train apart from a warning tone / message to the driver allowing talkback to be used. I believe the 95 stock was designed like this from new, and therefore never got the 'PEAB' modification which the other stocks received. I'm not sure where the 96 stock fits in to this and don't have the relevant stock handbook immediately to hand as I write this, however I know they have a PEA cut out switch, so I would strongly suspect they were similarly designed. (As an aside, there are certain defect scenarios which would cause the brakes to apply outside of the platform timer, for example if the Door Prove & PEA MCB trips or a fault on the actual PEA circuit!). Under TBTC, the platform leaving timer is replaced by the TBTC system, and the function is now controlled via the VOBC by means of a relay (from memory it's called the 'ATO PEA Relay' if I recall correctly), with this system the PEA is indeed linked in to the signalling. I've never had the experience, but I believe if within station limits the train will emergency brake with a TOD message 'Train EB Applied'. Again, the options are to cut out the circuit, or reset the handle. One anomoly is the Kennington Loop which has a pseudo-platform, in this case a train in a protected mode would run as far as the pseudo-platform, but will not go further until either of the two above options happen. Again I don't have direct experience, but I would strongly suspect the 96 stock is the same. |
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Post by Deleted on May 27, 2014 23:27:59 GMT
Thank you  I only ever had the posters I used to read when I was bored as a child to go on - white on green - some of them have resurfaced now. They say something along the lines of 'if any part of the train is in the platform the driver will stop immediately, otherwise it will continue to the next station where help can be given more easily'. I guess technicalities aren't really of interest there, a clear and concise message is a lot more important. |
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I only ever had the posters I used to read when I was bored as a child to go on - white on green - some of them have resurfaced now. They say something along the lines of 'if any part of the train is in the platform the driver will stop immediately, otherwise it will continue to the next station where help can be given more easily'. I guess technicalities aren't really of interest there, a clear and concise message is a lot more important.
