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Post by programmes1 on Oct 28, 2020 13:12:50 GMT
When the depot signalling was upgraded did the actual signals change in appearance as well or did they remain the same. I think it was 2 reds when at danger and 1 white when clear.
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Deleted
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Post by Deleted on Oct 28, 2020 18:16:28 GMT
Signals remained the same BR type 3 aspect shunt signal
The track circuits were removed and axle counters were installed
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Post by philthetube on Oct 28, 2020 18:49:13 GMT
They appear the same, however, the old ones showed 1 white or 2 reds, the new show 2 of either.
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Post by programmes1 on Oct 29, 2020 7:35:05 GMT
They appear the same, however, the old ones showed 1 white or 2 reds, the new show 2 of either. Thanks for the replies and it is interesting that the signals have been altered. No more track circuits does that cause problems with short trains when shunting or is there electronic logic to prevent such things. |
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Post by brigham on Oct 29, 2020 8:49:36 GMT
Looks like the 'two-reds' aspect appeared after 1996. I didn't know that.
It's general, not just a Neasden thing.
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Tom
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Post by Tom on Oct 29, 2020 14:45:49 GMT
Neasden was always 'two reds' and pre-dated main line practice.
The signal heads used were all changed on resignalling, and I believe they all moved slightly.
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DWS
every second count's
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Post by DWS on Oct 29, 2020 16:40:20 GMT
Also the shunt signals in Neasden depot have no-code letters only numbers .
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Post by philthetube on Oct 29, 2020 17:32:03 GMT
The red/white signals do not, as stated, but the entry exit shunt signals do, these are controlled by Baker St. or wherever they are now?
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Tom
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Post by Tom on Oct 29, 2020 20:25:40 GMT
Neasden and Wembley Park Interlocking Machine Rooms with remote control from Baker Street.
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Post by underover on Oct 30, 2020 20:16:33 GMT
They appear the same, however, the old ones showed 1 white or 2 reds, the new show 2 of either. Thanks for the replies and it is interesting that the signals have been altered. No more track circuits does that cause problems with short trains when shunting or is there electronic logic to prevent such things. Why would a short train cause a problem if there are axle counters? You count axles in (get a red if trying to enter, and will only clear only that number of axles has been counted off) They shunt the 3 car D78 from time to time which poses no issues |
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Deleted
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Post by Deleted on Oct 30, 2020 23:09:32 GMT
What goes in to a axle block section must come out
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Post by programmes1 on Oct 31, 2020 7:29:49 GMT
Thanks for the replies and it is interesting that the signals have been altered. No more track circuits does that cause problems with short trains when shunting or is there electronic logic to prevent such things. Why would a short train cause a problem if there are axle counters? You count axles in (get a red if trying to enter, and will only clear only that number of axles has been counted off) They shunt the 3 car D78 from time to time which poses no issues What I was getting at was axle counters have to be operated so a short train may be a problem unless there are axle counters to cover this possible problems It mat be that when a train shunts it has to complete the routes? therefore no problem but do staff not carry out such moves taking short cuts. I believe some depots had a number of derailments following such moves. I know Neasden depot is different in that it is signalled unlike others unless there are others. I have heard other stories about where a vehicle (not a train) has worked in an area but when they wanted to run trains they could not. |
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Post by philthetube on Oct 31, 2020 9:09:03 GMT
they have had signals remaining at danger on the Chesham branch following Pway work where a trolly has passed over the axle counters one way but not when returning.
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Tom
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Post by Tom on Oct 31, 2020 10:01:49 GMT
Indeed - there are two big weaknesses with Axle Counter sections compared to track circuits:
Trolleys or road rail vehicles entering a section and then leaving the track mid-section
The ability to remember there were axles in section when they come back on following a power cessation.
Personally I think Axle Counters were a bad idea for most of Neasden Depot - but the world seems to have declared war on track circuits.
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Post by programmes1 on Oct 31, 2020 12:22:12 GMT
Indeed - there are two big weaknesses with Axle Counter sections compared to track circuits: Trolleys or road rail vehicles entering a section and then leaving the track mid-section The ability to remember there were axles in section when they come back on following a power cessation. Personally I think Axle Counters were a bad idea for most of Neasden Depot - but the world seems to have declared war on track circuits. Thanks Phil/Tom That's what I meant by short trains / short shunt. |
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Deleted
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Post by Deleted on Oct 31, 2020 16:12:59 GMT
It wouldn’t make any difference if 32 axles for a full S8 is seen to go into the block but it only saw 16 go out then the section will go disturbed and a mismatch alarm would occur.
Before any reset is even contemplated a check must occur to make sure the section is clear of any obstructions.
The system doesn’t care on the length of a train in fact a failed Jub train was pushed into Neasden during a cancelled engineering hours so in total a 14 car length train went through without issues.
Maximum axles it can count in one go is 512 its 0 to 511
Chesham is a very old rudimentary system but the principal is the same
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Post by underover on Oct 31, 2020 20:35:02 GMT
Why would a short train cause a problem if there are axle counters? You count axles in (get a red if trying to enter, and will only clear only that number of axles has been counted off) They shunt the 3 car D78 from time to time which poses no issues What I was getting at was axle counters have to be operated so a short train may be a problem unless there are axle counters to cover this possible problems It mat be that when a train shunts it has to complete the routes? therefore no problem but do staff not carry out such moves taking short cuts. I believe some depots had a number of derailments following such moves. I know Neasden depot is different in that it is signalled unlike others unless there are others. I have heard other stories about where a vehicle (not a train) has worked in an area but when they wanted to run trains they could not. That makes sense, but I think the axle counters are at the start and finish of every section a train could end up (so its counted in and out). Yes though, you are quite right they only work if the train has operated them, regardless of length. |
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Post by philthetube on Oct 31, 2020 22:49:05 GMT
The signalling a Neasden does seem to be quite reliable, so can't be all bad.
The issue with Chesham is that it is a long walk for someone to check that the track is clear. (Nice views though).
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Tom
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Post by Tom on Nov 1, 2020 0:06:28 GMT
Indeed - there are two big weaknesses with Axle Counter sections compared to track circuits: Trolleys or road rail vehicles entering a section and then leaving the track mid-section The ability to remember there were axles in section when they come back on following a power cessation. Thanks Phil/Tom That's what I meant by short trains / short shunt. As @aetearlscourt has said, there's no problem with doing a short shunt with Axle Counters; as long as the same number of axles that have gone in come back out. |
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Post by programmes1 on Nov 1, 2020 8:21:16 GMT
Thanks all clear now I thought there would be just one axle counter for each section but just like blockjoints.
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