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| Class 9 on the East London Line! 09/04/2010 at 14:59 #1096 | |
GeoffM
6281 posts |
Proposals are afoot to allow the use of class 3 and class 9 to be designated as passenger services. Previously 9 was used for Eurostars (and long before that, unfitted freights), and also for certain priority Cross Country services. Apparently the ELL won't have enough class 1 and class 2 headcodes - presumably due to density of service.
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| Class 9 on the East London Line! 09/04/2010 at 14:59 #8316 | |
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GeoffM
6281 posts |
Proposals are afoot to allow the use of class 3 and class 9 to be designated as passenger services. Previously 9 was used for Eurostars (and long before that, unfitted freights), and also for certain priority Cross Country services. Apparently the ELL won't have enough class 1 and class 2 headcodes - presumably due to density of service.
SimSig Boss Log in to reply |
| Class 9 on the East London Line! 09/04/2010 at 15:38 #8318 | |
Noisynoel
989 posts |
It's not a proposal any longer it's a definate. The lack of headcodes comes with the amount used between New Cross Gate & West Croydon coupled with the intensity of the service. Wondr how long before a signaller tries putting a Class 9 from West Croydon into New Cross Gate goods... oh hang on, it's gone!
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| Class 9 on the East London Line! 09/04/2010 at 16:06 #8320 | |
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GeoffM
6281 posts |
It's still a proposal according to the documentation I received today - dated April 9th. But it is classed as "urgent" and any comments/objections need to be in by Monday! So officially it's still a proposal but I agree that it's definitely going to happen.
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| Class 9 on the East London Line! 09/04/2010 at 17:37 #8322 | |
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Danny252
1461 posts |
The Simsig manual says that in cases like these, code could be recycled over a day - i.e. run 2D00-2D99, and then loop back (as 2D00 has finished by then, in theory) - is this actually a possible practise, or are there far too many trains here even for that?
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| Class 9 on the East London Line! 09/04/2010 at 17:53 #8324 | |
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Noisynoel
989 posts |
The schedules are already in TRUST so let's hope it doesn't get thrown out now then! DAnny, it is possible to reuse numbers, however, the major issue is finding a number sequence that fits between NXG & West Croydon and on the NLL as well (In preperation for the future extension. Almost every letter is in use over either section of line. Noisynoel Log in to reply |
| Class 9 on the East London Line! 10/04/2010 at 16:22 #8357 | |
DriverCurran
682 posts 
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Noisynoel said:Wondr how long before a signaller tries putting a Class 9 from West Croydon into New Cross Gate goods... oh hang on, it's gone!Am sure that wont stop them trying :) Paul You have to get a red before you can get any other colour Log in to reply |
| Class 9 on the East London Line! 11/04/2010 at 00:22 #8369 | |
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Helper
20 posts |
It's long beyond the time when headcodes/service codes need to be re-thought to cover the vast increase in services since privatisation. What are the implications and possibility of a headcode re-structure.
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| Class 9 on the East London Line! 11/04/2010 at 00:38 #8370 | |
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Danny252
1461 posts |
How many freights actually run with class 8 headcodes these days, and would it matter too much if these were bunched under class 7? Admittedly I can see why 3 and 9 would be picked first for new passenger services - with both being ingrained on the minds of signalmen as fairly fast services (provided said signalmen weren't so old they tried to route a class 9 onto NXG goods!)
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| Class 9 on the East London Line! 11/04/2010 at 11:09 #8376 | |
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GeoffM
6281 posts |
Helper said:What are the implications and possibility of a headcode re-structure.One day they plan to go to six character headcodes. Of what form (ie digit, letter, digit, digit) I don't know. But the impact is pretty huge which is why it hasn't happened. Lots of software use fixed four-character fields for data storage and within messages between systems. Some software TRE are in the process of producing for Network Rail stipulates that provision for six character headcodes should be made. Danny252 said: How many freights actually run with class 8 headcodes these days, and would it matter too much if these were bunched under class 7?There are a few, deicers and sandites that I can think of off hand. It could cause a few regulation problems if the signallers didn't realise the limited speed if they were to be class 7s instead. Danny252 said: The Simsig manual says that in cases like these, code could be recycled over a day - i.e. run 2D00-2D99, and then loop back (as 2D00 has finished by then, in theory) - is this actually a possible practise, or are there far too many trains here even for that?They can and do recycle numbers throughout the day on Network Rail. North London Line number wrap around twice; so do the 2Jxx from Liverpool Street to Gidea Park that I can think of. Noel can probably correct me on this but I believe there is a time window in which headcodes shouldn't be reused, perhaps 6 hours. SimSig Boss Log in to reply |
| Class 9 on the East London Line! 11/04/2010 at 16:53 #8397 | |
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AnyFile
101 posts |
Is the letter required to be the second character or is it possible to use headcodes like 12A4 or 123B? Are headcodes like these already in use? Would this a possible solution? Log in to reply |
| Class 9 on the East London Line! 11/04/2010 at 17:11 #8403 | |
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GeoffM
6281 posts |
AnyFile said:Is the letter required to be the second character or is it possible to use headcodes like 12A4 or 123B?Some antiquated systems do require a letter but newer systems handle a digit there. When Eurostars used to transfer to/from Network Rail territory at Dollands Moor / Ashford / Fawkham Junction their headcodes of 91xx and 90xx used to be automatically converted to 9Ixx and 9Oxx (ie letters i and o instead of digits 1 and 0). SimSig Boss Log in to reply |
| Class 9 on the East London Line! 11/04/2010 at 21:52 #8416 | |
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benstafford
88 posts |
If they used letters and numbers for the last two digits, it would give 1296 possibilities for each destination letter instead of 100. Should be more than enough. A 4 letter combination would cover potentially 456000 numbers which should give every train a unique code.
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| Class 9 on the East London Line! 12/04/2010 at 08:56 #8420 | |
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GoochyB
222 posts |
Even changing the last 2 digits of the code to hexadecimal based numbers (i.e. 0-9, A-F) would increase the number of possibilities from 100 to 256.
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