|
Post by danwoodhouse on Oct 12, 2018 1:03:51 GMT
Can someone please tell me why is it that the doors on more modern stocks always take X seconds longer to open than the old trains
i remember many times on D stock (if you had the right driver) you could keep the passenger door open button depressed, the enable light would come on and the door would fly open while the train was still moving
|
|
|
Post by t697 on Oct 12, 2018 4:26:11 GMT
Comparing S stock with D stock, the doors are train speed interlocked so the train speed has to be nearer to zero before the doors can open. Also the Correct Side Door Enable 'windows' are tighter in most locations to fit the longer train safely into the available platform length. Against that, once the doors start to open the opening grows and is usable quicker than on D stock because it's in the middle of the doorway and there are two doors opening and generating the opening. In any case, Holding the Open buttons pressed and relying on CSDE and the train speed interlock was not trained safe practice.
On LUL lines with ATC signalling which provides the CSDE there can be a short delay as the train stops before CSDE is asserted. Something for ATC suppliers to improve on for the future!
|
|
|
Post by jetblast787 on Oct 12, 2018 7:49:27 GMT
I've noticed the 09 stock doors have the 'flying stop' feature where the doors open a split second before the train comes to a stop. Not as early as the existing D stock but it is noticeable. Is it intentional?
|
|
|
Post by goldenarrow on Oct 12, 2018 8:11:55 GMT
I've noticed the 09 stock doors have the 'flying stop' feature where the doors open a split second before the train comes to a stop. Not as early as the existing D stock but it is noticeable. Is it intentional? This was picked up upon when the 09 stock was new, back then the doors would release as you say but sometimes the emergency door release failsafe would activate and slow the door leaf from opening (video of that scenario below). Not sure that it has been written in to the Vic line books, but it’s pretty normal now to see the doors open on Vic once the train is down to 2mph with no hindrance. I know there were a few cases in 2017 (including one I witnessed) on the Met line where certain drivers where releasing the doors before they had “dropped the handle” causing a flying stop which was and I believe still is frowned upon. As promised, here we see what I described above.
|
|
|
Post by MoreToJack on Oct 12, 2018 10:04:17 GMT
It all comes down to however the trains and signalling systems are configured.
On conventionally signalled lines, the door buttons are enabled once the train is within the CSDE (Correct Side Door Enable - remember to explain acronyms please folks) loop (generally the length of the platform) and is travelling at less than 2mph.
On ATO lines, it depends on which signalling system is in use, and how it deals with the door systems.
The Victoria line uses 'conventional' CSDE, as mentioned above, which is why it is sometimes possible for the doors to open before the train has come to a stop.
On SelTrac/TBTC signalled lines (Jubilee and Northern), the ability to open the doors is a core part of the signalling system. Trains must receive an 'Accurate Stop' (AS) before the doors can be released. This will also be the case under CBTC on the Sub-Surface.
The Central line also uses 'conventional' CSDE, and again in theory the doors could open before the train has stopped.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Oct 12, 2018 13:37:46 GMT
It all comes down to however the trains and signalling systems are configured. On conventionally signalled lines, the door buttons are enabled once the train is within the CSDE (Correct Side Door Enable - remember to explain acronyms please folks) loop (generally the length of the platform) and is travelling at less than 2mph. On ATO lines, it depends on which signalling system is in use, and how it deals with the door systems. The Victoria line uses 'conventional' CSDE, as mentioned above, which is why it is sometimes possible for the doors to open before the train has come to a stop. On SelTrac/TBTC signalled lines (Jubilee and Northern), the ability to open the doors is a core part of the signalling system. Trains must receive an 'Accurate Stop' (AS) before the doors can be released. This will also be the case under CBTC on the Sub-Surface. The Central line also uses 'conventional' CSDE, and again in theory the doors could open before the train has stopped. The legacy CSDE loop is not the whole platform but will allow the train to open its doors within 1.7metres of it Could it just be the fact the old trains used a air motor to open the door as opposed to modern trains which use electric motors
|
|
|
Post by t697 on Oct 14, 2018 14:20:24 GMT
The Victoria line uses 'conventional' CSDE, as mentioned above, which is why it is sometimes possible for the doors to open before the train has come to a stop. On SelTrac/TBTC signalled lines (Jubilee and Northern), the ability to open the doors is a core part of the signalling system. Trains must receive an 'Accurate Stop' (AS) before the doors can be released. This will also be the case under CBTC on the Sub-Surface. The Central line also uses 'conventional' CSDE, and again in theory the doors could open before the train has stopped. The legacy CSDE loop is not the whole platform but will allow the train to open its doors within 1.7metres of it Could it just be the fact the old trains used a air motor to open the door as opposed to modern trains which use electric motors Victoria and Central lines have the CSDE as a function of the ATC, not a stand alone system. The Victoria line video shows it's integrated in a way that doesn't give a delay on stopping before the doors can be opened. Other threads on here have commented about delays on another ATC system! With the four Sub-Surface lines going over to ATC in the next few years, on LUL "conventional CSDE" will mean provided by the ATC not as a separate system! The 09TS and S stock trains with electric door operators don't have delay as a result of that by comparison with air operated door systems, indeed if anything they are marginally quicker.
|
|