|
|
Post by nicop on Jul 4, 2018 23:49:38 GMT
First thread... now time for making a fool of myself.  I'm intrigued why sometimes on the Picc trains enter the platforms sometimes so slowly. There is significant braking in the tunnel sections and crawls into the platforms... Some of the Bakerloo line drivers seem to be attempting to break the sound barrier when entering the platform but on the Picc it's significantly slower. Then there's the odd driver who flies into the platform, so it's not something to do with the braking arcs? Surely this is slowing down the service? I can understand on open air stations to prevent wheel flats.. but tunnel sections - is there a reason? |
|
|
|
Post by principlesdesigner on Jul 5, 2018 0:04:25 GMT
This will be where "draw-up" or speed controlled signals are provided. Basically, where there are short sections, the full speed overlap extends too far ahead, so the following train would not be able to enter the platform, so, the signals before the station, home signals, are held at red until the train is proved to be travelling slowly enough for the reduced starter overlap. Often, there is either an additional signal, or trainstop provided in the platform for speed control purposes, and will be numbered with an extra 0 e.g. OP200, so that the driver is aware of their purpose.
|
|
North End
Beneath Newington Causeway
Posts: 1,355
|
Post by North End on Jul 5, 2018 0:39:14 GMT
First thread... now time for making a fool of myself. I'm intrigued why sometimes on the Picc trains enter the platforms sometimes so slowly. There is significant braking in the tunnel sections and crawls into the platforms... Some of the Bakerloo line drivers seem to be attempting to break the sound barrier when entering the platform but on the Picc it's significantly slower. Then there's the odd driver who flies into the platform, so it's not something to do with the braking arcs? Surely this is slowing down the service? I can understand on open air stations to prevent wheel flats.. but tunnel sections - is there a reason? I get the impression the Picc has become a little over defensive in the last decade. Certainly I’ve noticed some pretty appalling driving on there recently. There are a number of possible reasons for this. Certainly it’s quite possible to enter tunnel platforms at 30-35 mph unless there’s a lower speed limit or some other reason. Anything below 30 and it may (or at least should) get flagged up during a competence assurance assessment. |
|
tut
Posts: 2,371 
|
Post by tut on Jul 5, 2018 0:53:53 GMT
This will be where "draw-up" or speed controlled signals are provided. Basically, where there are short sections, the full speed overlap extends too far ahead, so the following train would not be able to enter the platform, so, the signals before the station, home signals, are held at red until the train is proved to be travelling slowly enough for the reduced starter overlap. Often, there is either an additional signal, or trainstop provided in the platform for speed control purposes, and will be numbered with an extra 0 e.g. OP200, so that the driver is aware of their purpose. I had the thought too, but I'm not sure there are any draw ups in the tunnel sections of the Picc. Obviously there's some at Arnos Grove, but that isn't in tunnel of course.
There was never an OP200, 20 lever controls points and OP2 is the inner rail home to platform 4 - or was it just an example?  |
|
|
|
Post by PiccNT on Jul 5, 2018 1:42:30 GMT
We have two draw up signals, PJ320 halfway down platform 4 at Arnos Grove WB and L100 just prior to entering Kings X WB but they will only be active if there is a conflicting move taking place, both there to protect the converging junction ahead. I'm a bit of a flyer myself and would normally hit the platform at around 30mph. I do travel and have travelled with a lot of drivers on my line and North End is right, there are some drivers that don't appear to be able to drive at line speed and are over cautious coming into platforms.
It depends of course what time of day you're talking about. Plus we seem to be having no end of issues that results in driving "stick to stick" so that is maybe part of it also.
|
|
MoreToJack
Global Moderator
Stroking & restroking
Posts: 1,368
|
Post by MoreToJack on Jul 5, 2018 1:46:22 GMT
This will be where "draw-up" or speed controlled signals are provided. Basically, where there are short sections, the full speed overlap extends too far ahead, so the following train would not be able to enter the platform, so, the signals before the station, home signals, are held at red until the train is proved to be travelling slowly enough for the reduced starter overlap. Often, there is either an additional signal, or trainstop provided in the platform for speed control purposes, and will be numbered with an extra 0 e.g. OP200, so that the driver is aware of their purpose. I had the thought too, but I'm not sure there are any draw ups in the tunnel sections of the Picc. Obviously there's some at Arnos Grove, but that isn't in tunnel of course.
There was never an OP200, 20 lever controls points and OP2 is the inner rail home to platform 4 - or was it just an example? Of course, none the draw ups still exist at OP and instead there is the (unique for LU) Variable Speed Signage (VSS) system. |
|
|
|
Post by principlesdesigner on Jul 5, 2018 3:37:30 GMT
This will be where "draw-up" or speed controlled signals are provided. Basically, where there are short sections, the full speed overlap extends too far ahead, so the following train would not be able to enter the platform, so, the signals before the station, home signals, are held at red until the train is proved to be travelling slowly enough for the reduced starter overlap. Often, there is either an additional signal, or trainstop provided in the platform for speed control purposes, and will be numbered with an extra 0 e.g. OP200, so that the driver is aware of their purpose. I had the thought too, but I'm not sure there are any draw ups in the tunnel sections of the Picc. Obviously there's some at Arnos Grove, but that isn't in tunnel of course.
There was never an OP200, 20 lever controls points and OP2 is the inner rail home to platform 4 - or was it just an example? it was just an example I dreamed up! |
|
|
|
Post by superteacher on Jul 5, 2018 6:59:29 GMT
Mainly it’s down to overly defensive driving. There have been very little signalling changes since the 80s and back then trains would fly into platforms.
Unnecessary speed limits have also been implemented in places. I can’t believe how slow the trains enter the tunnel at Barons Court these days. I miss the days when it was full pelt into the tunnel down to Earls Court.
There’s also Kings Cross southbound, where trains just seem to poodle in save for the odd driver.
|
|
rincew1nd
Administrator
Junior Under-wizzard of quiz
Posts: 8,694
|
Post by rincew1nd on Jul 5, 2018 7:50:32 GMT
There's a fine fine line between overly-bold, defensive and excessively-cautious. I noticed two extremes the other day on the big railway: Click here if embedded tweet fails to display. |
|
|
|
Post by superteacher on Jul 5, 2018 8:03:34 GMT
There is a different culture nowadays. Many years ago the timetables were less forgiving and if you drove slowly you would run late. The mantra then was to enter platforms quixk and brake later.
|
|
tut
Posts: 2,371
|
Post by tut on Jul 5, 2018 9:25:43 GMT
I had the thought too, but I'm not sure there are any draw ups in the tunnel sections of the Picc. Obviously there's some at Arnos Grove, but that isn't in tunnel of course.
There was never an OP200, 20 lever controls points and OP2 is the inner rail home to platform 4 - or was it just an example? it was just an example I dreamed up!
Ahhhh Hopefully you were interested all the same There did used to be OP280, OP290, OP300, OP600 and OP700, but as MoreToJack says, all gone now |
|
|
|
Post by principlesdesigner on Jul 5, 2018 10:05:37 GMT
tut - thanks for this, I am interested, and indeed started some work on the replacement of Edgware Road cabin, before the original proposal was scrapped!
|
|
|
|
Post by A60stock on Jul 5, 2018 10:49:08 GMT
Ive also noticed another thing, on the shared sections with the district and met lines. I have used Eastcote station many times and notice how the s8 stock rushes into the platform at full pelt whilst the 73 stock comes in significantly slower? Is there a reason for this?
|
|
|
|
Post by PiccNT on Jul 5, 2018 11:04:10 GMT
Mainly it’s down to overly defensive driving. There have been very little signalling changes since the 80s and back then trains would fly into platforms. Unnecessary speed limits have also been implemented in places. I can’t believe how slow the trains enter the tunnel at Barons Court these days. I miss the days when it was full pelt into the tunnel down to Earls Court. There’s also Kings Cross southbound, where trains just seem to poodle in save for the odd driver. There are some drivers that do enter the tunnel full pelt. They then fail the 25mph timing section and then SPaD A655! Ive also noticed another thing, on the shared sections with the district and met lines. I have used Eastcote station many times and notice how the s8 stock rushes into the platform at full pelt whilst the 73 stock comes in significantly slower? Is there a reason for this? The S stock trains have a higher speed limit than our trains plus their brakes are less erratic than ours! All station starters between Eastcote and Hillingdon do not clear until you have berthed in the platform so probably T/Ops just making sure they do stop! <<superteacher: posts merged>>
|
|
|
|
Post by rummer on Jul 5, 2018 11:14:09 GMT
I always hit the platforms at about 30mph any faster than that you couldn't trust the 73 brakes
|
|
