Black and Red buttons

[chris]

In all tube cabs i've seen photos/videos of, there is 1 black button and 2 red buttons for opening the doors (as pictured here): www.trainweb.org/districtdave/html/d78_stock_2.html

However, what are they all for? On a picc. Drivers Eye View the operator always uses the black button and never the two red ones. What are they for?

edit by AL: Changed the img tags to URL tags.

[Deleted]

Chris said:

However, what are they all for? On a picc. Drivers Eye View the operator always uses the black button and never the two red ones. What are they for?

Red: Open doors
Black: Close doors

There is too buttons to open the doors so it is a positive action, and something you cannot do by mistake. Then you have one button to close the doors!

[Deleted]

Chris said:

In all tube cabs i've seen photos/videos of, there is 1 black button and 2 red buttons for opening the doors (as pictured here): www.trainweb.org/districtdave/html/d78_stock_2.html

However, what are they all for? On a picc. Drivers Eye View the operator always uses the black button and never the two red ones. What are they for?

The question is actually answered beneath the picture that you've linked to above! However Met App has explained it for you anyway!

[chris]

AlanL said:

The question is actually answered beneath the picture that you've linked to above! However Met App has explained it for you anyway!

I did see it - I just didn't why there were two.

Cheers Met App

[Tom]

As a little international comparison, the Stockholm arrangement is exactly the opposite: Black to open the doors, red to close them.

As I'm sure Igelkotten will testify, this is always a source of great confusion to me, and I have been seen pressing the close button two or three times and wondering why the doors aren't opening!

[chris]

Met said:

Red: Open doors
Black: Close doors

So why do the picc. line drivers on the Drivers Eye View video press the black ones to open. (Though they do do it twice)

[igelkotten]

Tom said:

As a little international comparison, the Stockholm arrangement is exactly the opposite: Black to open the doors, red to close them.

As I'm sure Igelkotten will testify, this is always a source of great confusion to me, and I have been seen pressing the close button two or three times and wondering why the doors aren't opening!

Young engländer, ve haff vays off making you learn... ;D


And the idea behind the Stockholm colouring is, presumably, opening doors=potential danger, so therefore the buttons are red. The door system still has some weird things going on as a heritage from the times when we used crew-operated trains (up until 1980-81)

We didn't get any door interlock until the C6 stock in the early 1970'ies, and that one only cut the traction current and prevented the release of any brake when a door open impulse was given. Nowadays, the interlock has been modified, and most stock has been refitted with a speed sensor that requires the train to be at a standstill in order for the passenger saloon doors to be opened.

The C20 stock is fitted with something approximating the London Correct Side Door Enable, but it is only operational (and then only partly) on the green line. As a matter of fact, it is the door-enable loops for the ATO functionality that are used as a CSDE function. This system is, howver, not the most reliable one I have encountered.

/Igelkotten

[Deleted]

Chris said:

So why do the picc. line drivers on the Drivers Eye View video press the black ones to open. (Though they do do it twice)

They dont as it would close the doors, or do nothing i they were already closed!

[Dmitri]

As an international note, we use rather simple door interlocks that prevent train from motoring (of course, there is a magic "override" button somewhere ). No fancy things like speed sensors (so you can sometimes see doors being opened whilst train screeches its last metre before the stop) or CSDE (that's why I strongly suggest to take the "Don't lean" appeal seriously if you are approaching "wrong-side" station). Oh, almost forgot: door interlocks have "insensibility zone" of about a centimetre, so if you got a flap of your coat caught by the doors, most likely you'll have to wait for the next station.

Have a nice journey ;D!

[igelkotten]

Dmitri said:

As an international note, we use rather simple door interlocks that prevent train from motoring (of course, there is a magic "override" button somewhere ). No fancy things like speed sensors (so you can sometimes see doors being opened whilst train screeches its last metre before the stop) or CSDE (that's why I strongly suggest to take the "Don't lean" appeal seriously if you are approaching "wrong-side" station). Oh, almost forgot: door interlocks have "insensibility zone" of about a centimetre, so if you got a flap of your coat caught by the doors, most likely you'll have to wait for the next station.

Have a nice journey ;D!

Our speed sensors do have, sensibly enough, a slight margin built into them. The doors can be released at speeds of, I believe, 2,5 km/h or lower. Thus, if you are on the ball, you can bring your train to almost a complete standstill, release the brake completely and then open the doors, leading to a very soft and quick stop. Or, you can end up with a train that starts rolling along and going over the door release speed limit, forcing you to make a very abrubt stop and looking ever so clumsy.

Our old stock doors also have a margin built into them -the door halves can be pushed a few centimetres to each side, even when the door is mechanically locked. This was originally considered a safety feature, but has now become the target of so much abuse that it has become a source of safety problems.

The C20 doors do close tight, but have rubber seals that are soft-ish and can permit small things to become caught between them, with the doors still indicating that theyare properly locked and in control. This has led to several nasty incidents, including one where a passenger got his coat caught between a pair of doors and was dragged to his death by a starting train. The doors and the rubber seals have been a constant source of problems since day one, with several attempts at fixing one problem only leading to two new ones popping up. There are talks of starting a major rebuild programme in the autumn.

Now, on the old stocks, the door interlocks operated on the door open and close impulses from the buttons in the cab. That is, they did not care about the actual state of the doors -once a certain impulse was given, that determined the state of the door interlocks.

Thus, once you had given a door close impulse, you could technically drive away, even with scores of young hooligans haning on the outside of the train and holding the doors open. You did not get a "doors closed visual", of course, since the doors were not closed, and procedure-wise, you were certainly not permitted to drive your train in that state, but it was technically possible.

/igelkotten

[Dmitri]

Igelkotten said:

you can bring your train to almost a complete standstill, release the brake completely and then open the doors, leading to a very soft and quick stop. Or, you can end up with a train that starts rolling along and going over the door release speed limit, forcing you to make a very abrubt stop and looking ever so clumsy.

AFAIK our drivers are discouraged from releasing brakes whilst standing at the station, one of the main reason is a (mandatory since 1960s, I beleive) 3/1000 gradient which keeps water from accumulating.

The C20 doors do close tight, but have rubber seals that are soft-ish and can permit small things to become caught between them, with the doors still indicating that theyare properly locked and in control. This has led to several nasty incidents, including one where a passenger got his coat caught between a pair of doors and was dragged to his death by a starting train.

Are they that strong? Our doors aren't weak, but I've never heard of such incidents.

Now, on the old stocks, the door interlocks operated on the door open and close impulses from the buttons in the cab. That is, they did not care about the actual state of the doors -once a certain impulse was given, that determined the state of the door interlocks.

No, our door interlocks aren't nearly that sophisticated . To the best of my knowledge, they use limit switches. On 81-71x and refurbished E-series cars, opened doors are indicated with a white lamp on the side of the car. BTW, our doors are controlled with voltage levels, not impulses.

[Tom]

Igelkotten said:

Young engländer, ve haff vays off making you learn... ;D

How about we go to Odenplan siding, I hold the microphone with one hand and the cable run with the other...?

[igelkotten]

Dmitri said:

AFAIK our drivers are discouraged from releasing brakes whilst standing at the station, one of the main reason is a (mandatory since 1960s, I beleive) 3/1000 gradient which keeps water from accumulating.

I forgot to mention something: As soon as you give an door open impulse, you also get a full service brake application. Thus, you use the brake activation from the doors as the last application, bringing you to a standstill.

If you are standing at a station, open the doors and then move the controller handle to a certain position, you get a "holding brake" -about 120 kPa. Then, once you have closed the doors, you press the "quick start" button, which releases the brakes and applies maximum traction power.

You then have about five seconds to take over the controls and activate any vigilance device in the cab, otherwise the train goes into full service. If you are standing in front of a red signal, or has no door closed indication, pushing the "Quick Start" just sends you into full service brake.

Are they that strong? Our doors aren't weak, but I've never heard of such incidents.

Actually, the doors have a way to weak closing force -only 300N, which is low enough to cause a series of problems in itself. However, the C20 doors are slide-plug doors -once they are locked, they are mechanically locked with a locking bar going over a latch. The only way to open the doors then is to either give a door open impulse, or to use an emergency door opener, which mechanically disconnects the locking latch.

So, when the unfortunate man was caught in the doors, the doors locked around his coat, and the driver got a "doors locked indication" , that was it -he was stuck. Why no-one of the passengers witnessing this tragedy inside the car used the emergency communicator or the emergency alarm, which would have stopped the train, has never been answered. Their apathy cost the man his life.

No, our door interlocks aren't nearly that sophisticated . To the best of my knowledge, they use limit switches. On 81-71x and refurbished E-series cars, opened doors are indicated with a white lamp on the side of the car. BTW, our doors are controlled with voltage levels, not impulses.

We have a yellow outside light on the old stock, and a yellow inside light as well as a computer display on C20. On older stock, doors are operated by a doors closed multiple line running the length of the train. This line has to become energised for the doors to open. Thus, if power is lost, the doors remain closed.

C20 is of course completely digital, so there the multiple line uses a command signal. With C20, if power is lost, the doors remain in the same state they were before the power loss. If they were open, they remain open, if they were closed, they remain closed. However, upon activation ,part of the startup sequence for the train's control system is to send a door-close signal through the train and verify that all doors lock in position. Thus, the doors always close when power comes back.

The position detection of doors on both old and C20 stock is by mechanical limit switches, being triggered by the movement of the door mechanism through it's operational sequence. Fiddlign with those switches can give all sorts of itneresting results...

[igelkotten]

Tom said:

How about we go to Odenplan siding, I hold the microphone with one hand and the cable run with the other...?

Now, for everyone who does not know what Tom is talking about, here is the story:

A friend of mine was about to change ends in Odenplan siding, a dark and dank hole in the middle of the city. Somehow, he managed to catch his sleeve on one of the PA microphones on his way out of the cab. The PA microphones have a metal casing, by the way. The mic was thrown out of it's holder and landed on the metal grating of a cable run next to the walkway, producing a big spark.

A spark.

Hang on, aren't these things supposed to be earthed? Or is it the cable run that is not earthed? PANIC!!!

My friend made a understandably frantic call to line control, who also said Gulp! in unison and instructed him to walk very,very carefully to the other end of the train. The siding was then closed, and technical services called. Likewise, a pair of fitters were called out to his train to take a look at the cab.

Of course, infrastructure blamed rolling stock, and vice versa...

As it turned out, it was probably a case of shoddy insulation in the cab instruments. And a lot of bored drivers have a new hobby when turning at Odenplan. Some have even tried photographing them, and competiting on who can make the largest spark.

[Tom]

Igelkotten said:

And a lot of bored drivers have a new hobby when turning at Odenplan. Some have even tried photographing them, and competiting on who can make the largest spark.

A bored former AET has also had a go... likewise with the photographing bit. ;D

I did wonder when seeing the sparks what sort of voltage is present, I might have to take a multimeter with me next time I go to Stockholm.