03-01-2013, 01:14 PM
Well actually there have been this type of shortened overlap for many many years- the only way they are identified is by a usual full overlap symbol with a measurement against it which is less than the old standard 200 yards (183 then 180m). A line on which I am working is the Wimbledon brnach of the District Line 9signalled from NR's Wimbledon ASC to normal standards of the time but with the addition of trainstops) which has overlaps generally about 90m. Similarly the branch line that terminates at Richmond as OL marked as 150 (yards).
Certainly from memory the whole of the North London Line in the vicinity of Camden Road (at least prior to the resignalling of about 5 years ago for London Overground) had overlaps of less than 100m and indeed the AWS was similarly positioned at a similar distance prior to the signals (compliant with he standards of the time and delivberately done due to low line speed).
Hence I think it is a matter of "can't see wood for trees"; such suburban lines often feature such overlaps, but perhaps the clue goes unobserved as it doesn't stick out unless you know what you are looking for!
Certainly from memory the whole of the North London Line in the vicinity of Camden Road (at least prior to the resignalling of about 5 years ago for London Overground) had overlaps of less than 100m and indeed the AWS was similarly positioned at a similar distance prior to the signals (compliant with he standards of the time and delivberately done due to low line speed).
Hence I think it is a matter of "can't see wood for trees"; such suburban lines often feature such overlaps, but perhaps the clue goes unobserved as it doesn't stick out unless you know what you are looking for!
(03-01-2013, 09:32 AM)jenni.joseph9 Wrote: Hi,
Thank you for the detailed explanation.
Is there a case where a reduced overlap is considered. I tried to search that, but could not find one.
Can you help me with that, please, if you have one..
Thanks & Regards,
PJW