Phil
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RIP 23-Oct-2018
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Post by Phil on Sept 23, 2005 9:48:57 GMT
On mainline vacuum and air-braked stock, if you let go of the DSD the power is cut immediately but you have 7 seconds to get the handle back down before the emergency brake application starts. Is it the same with LU or is there a different delay (or none at all); and are all current stocks the same?
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Post by piccadillypilot on Sept 23, 2005 10:29:48 GMT
Is it the same with LU or is there a different delay (or none at all); and are all current stocks the same? No delay on LT/LU stock. Drop the button, the control circuits are broken and the brake goes in. |
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Post by igelkotten on Sept 23, 2005 10:38:07 GMT
Here in the Stockholm Metro, we also have no delay on the DSD. The results differ, though, depending on the stock. On the old stock with coffee-grinder handles (up to C5) you got an immediate emergency brake, on newer stock, you get a full service brake, including rheostatic or regenerative braking.
Swedish mainline stock generally has a delay of about eight seconds between letting go of the DSD and the brakes coming on.
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Deleted
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Post by Deleted on Sept 23, 2005 14:07:47 GMT
No delay on LT/LU stock. Drop the button, the control circuits are broken and the brake goes in. And the minute you reset the deadman, everything works again. Same as there isnt a time delay on the emcy brake releasing like there is on NR |
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Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
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Post by Phil on Sept 23, 2005 14:30:34 GMT
And the minute you reset the deadman, everything works again. Same as there isnt a time delay on the emcy brake releasing like there is on NR Ah- that makes sense now! Ta MA  |
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Post by Christopher J on Sept 23, 2005 19:49:39 GMT
On older SR Stock (CIGs/VEPs/CEPs/BEPs/ect) the Deadman system is installed into the Power Controller (see here - cjolly.mysnaps.org.uk/p20539737.html) if you drop the Power Controller you will destroy Brake Pipe Air into the Atmosphere to cause an Emergency Application of the Westinghouse Auto-Brake. You can release the Power Controller in Notch 0 as long as the Reverser next to it is in the Neutral position and not vent the Brake Pipe air to the world, but this works at any speed, not just when the Train is stationary, I remember being on an 8CIG going down the Haslemere line towards Portsmouth at 90mph, I look into the cab (you can see into the cab from the door between the cab and the passenger saloon) and the drivers got the Deadman dropped in Neutral, the Drivers Brake Valve in his left hand, and his Mobile in his right texting away!!!  |
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Deleted
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Post by Deleted on Sept 23, 2005 21:59:48 GMT
I look into the cab (you can see into the cab from the door between the cab and the passenger saloon) and the drivers got the Deadman dropped in Neutral, the Drivers Brake Valve in his left hand, and his Mobile in his right texting away!!! Iam very surpised to hear that, as that means you have not got a deadman, which is very very odd. I wouldnt have thought that would have been possible. |
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Tom
Administrator
Signalfel?
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Post by Tom on Sept 23, 2005 22:49:48 GMT
My understanding was that the DSD was a foot pedal?
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Phil
In memoriam
RIP 23-Oct-2018
Posts: 9,473
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Post by Phil on Sept 23, 2005 23:12:31 GMT
No- the pedal is a vigilance device which must be activated after a certain time (usually 60 sec) to prevent an emergency brake application. Trains normally have one or the other, not both, but the vigilance device is considered to be more effective therefore safer.
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Post by q8 on Sept 23, 2005 23:13:55 GMT
It was perfectly possible to put the controller into off and centralise your reverser key and let the train toddle merrily along at any speed in my time. Given the right gradients and conditons a train will roll for miles if you let it. We often used to coast along on Sundays as there was bags of time and not that many passengers.
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Post by igelkotten on Sept 24, 2005 0:12:04 GMT
No- the pedal is a vigilance device which must be activated after a certain time (usually 60 sec) to prevent an emergency brake application. Trains normally have one or the other, not both, but the vigilance device is considered to be more effective therefore safer. Do note that there is quite a lot of confusion and variation in the terminology used between various countries. What one calls a vigilance device is another's alerter safety switch and so on. As regardign viginalce devices that have to be acknowledged or operated every once in a while, they are now generally considered to be not as effective as once believed. The thing is, acknowledging or operating a vigilance device is a repetitive task, and the human mind has an amazing ability to start performing repetitive tasks without thinking about them. This is usually very good, since it, among other things, enables us to walk and chew bubblegum at the same time. On the other hand, it has also made drivers acknowledge vigilance device warnings without conciously registering them. There are several documented cases of drivers being sound asleep and still merrily hitting the acknowledge button every 60 seconds. |
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Deleted
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Post by Deleted on Sept 24, 2005 0:30:14 GMT
"For every foolproof device, there is a fool against whom the device is not proof....."
Some Sydney trains had a pedal that had to be kept depressed. Drivers complained that the return spring was too strong and their legs hurt, so a weaker spring was fitted. Then a grossly obese driver died of heart attack at the top of a down grade, and the weight of his leg kept the pedal down. The train came off the rails on a curve and several passengers were killed.
CityRail is thinking about whether it should change the pedals......
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Deleted
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Post by Deleted on Sept 24, 2005 1:42:49 GMT
I know this is slightly off-topic, but on the Thames Turbo units (and I believe most of the more modern DMU's), the DSD and Vigilance are all in the same foot pedal.
For the DSD, you have to keep the pedal depressed all the time (unless stationary). If you release it, you hear an alarm and the brakes will kick in after a certain amount of time.
The vigilance part of it was about every minute, you'd hear a beeping noise, and you had to take your foot off the pedal briefly and then put your foot back down again.
I remember a few units with sticky foot pedals which released ok, but took a few attempts to slam them back down to cancel the vigilance!
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Post by Christopher J on Sept 24, 2005 9:47:31 GMT
My understanding was that the DSD was a foot pedal? No foot pedal DSDs on the Slammers. On some other NR stock (Classes 313-314-315) the driver has a choice of either holding the Power Controller down or a Foot Pedal DSD on the floor. |
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Post by doubletrigger on Sept 24, 2005 12:01:43 GMT
You can release the Power Controller in Notch 0 as long as the Reverser next to it is in the Neutral position and not vent the Brake Pipe air to the world, From Atmosphere to World, make up your mind! |
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Post by Dmitri on Oct 2, 2005 14:36:32 GMT
Iam very surpised to hear that, as that means you have not got a deadman, which is very very odd. I wouldnt have thought that would have been possible. Do you know that we don't have deadman on all kinds of the metro rolling stock  ? |
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Post by markextube on Oct 2, 2005 22:46:51 GMT
I had a couple of 95's. Dropped the deadman as i needed to and nothing happened? That didn't make the papers.
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