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Post by Deleted on Mar 15, 2017 18:32:16 GMT
I thought I'd open up a thread here specifically to talk about the resignalling of the SSR. A few questions to start us off then: - I've been wondering - what is the actual name of the ATC product that is being installed on the SSR. Is it appropriate to refer to it as TBTC and/or SelTrac or not?
- To what extent is it different from the system employed on the Jubilee and Northern, and is there any chance of future interworking? I know on the Jubilee (and Northern) they use the two orange wires in the four-foot, whereas the SSR will use radio transmitters, so presumably any interworking would, at the very least, require the fitting of a suitable receiver, or a standardisation of communication method.
- After resignalling, how will Hammersmith Depot/Sidings be controlled?
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Post by crusty54 on Mar 15, 2017 20:03:44 GMT
this is the description - Thales CBTC Seltrack solution this page gives a lot of information (fairly recent) www.railengineer.uk/2016/08/24/4lm1/Hammersmith Depot will disappear and become just sidings. It is the site of the Control Centre. |
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Post by Deleted on Mar 15, 2017 20:05:05 GMT
To answer your question
Seltrac CBTC (Communication Based Train Control) as opposed to TBTC (Transmission Based Train Control)
Basic difference is that instead of the red not orange loops in the 4 foot, we will use RFID tags and radio aerials to do the same job as JNP have suffered from breakages due to items being dropped onto it as it is fibre cable. We will still use axle counters where more precise train location is required I.e points or current speed control locations.
Hammersmith Sidings will be fully automated the new electric points (Surelocks) at the moment are worked by the shunter with a local control panel on each set currently.
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Post by crusty54 on Mar 16, 2017 0:42:24 GMT
I did question the wisdom of fixing the cable to the trackbed on the Jubilee line at a pre-start briefing meeting.
This followed the DLR experiencing problems and raising it into protected runs.
Lessons learned for the 4LM.
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North End
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Post by North End on Mar 16, 2017 1:06:14 GMT
I did question the wisdom of fixing the cable to the trackbed on the Jubilee line at a pre-start briefing meeting. This followed the DLR experiencing problems and raising it into protected runs. Lessons learned for the 4LM. Yes it's a menace to walk on, with JNUP they really did choose the worst possible location to locate the cables from a track walking perspective. It adds complication when engineering work takes place too. I believe the 4LM system will allow a slightly quicker re-entry process for non-communicating trains, which will certainly be useful particularly on the Met in the autumn. I wonder if the wheelslide/NCT design flaw that so badly affects JNUP will be eased or even designed out? Papers I have seen suggest LU has not been able to crack this challenge on JNUP despite a fair bit of work, and we thus appear condemned to pathetic brake rates in the open for the foreseeable future. I hope to be proved wrong on his. Back on the subject of the inductive cables, there have been a fair few incidents where trains have lost shoes thus wrecking the cable in the process. 95 and 96 stocks are rather prone to losing shoes. A good supply of doorstops for LU office accommodation if nothing else, although technically I suppose the 95 stock ones at least remain property of Alstom! A few find their way into people's equipment bags as a practical joke too, particularly at one depot. |
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Post by trt on Mar 16, 2017 15:41:13 GMT
To answer your question Seltrac CBTC (Communication Based Train Control) as opposed to TBTC (Transmission Based Train Control) Basic difference is that instead of the red not orange loops in the 4 foot, we will use RFID tags and radio aerials to do the same job as JNP have suffered from breakages due to items being dropped onto it as it is fibre cable. We will still use axle counters where more precise train location is required I.e points or current speed control locations. Hammersmith Sidings will be fully automated the new electric points (Surelocks) at the moment are worked by the shunter with a local control panel on each set currently. Fibre? That to me smacks of optical transmission which clearly it isn't. |
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Post by Deleted on Mar 16, 2017 16:11:02 GMT
It is a Fibre cable
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Post by Deleted on Mar 16, 2017 17:26:58 GMT
this is the description - Thales CBTC Seltrack solution this page gives a lot of information (fairly recent) www.railengineer.uk/2016/08/24/4lm1/Hammersmith Depot will disappear and become just sidings. It is the site of the Control Centre. There is still a desire to do some maintenance at Hammersmith and the wash will still be there (as will all the depot buildings) so I don't think it correct to say it will disappear. Also the control centre is at Hammersmith but on the opposite side of the tracks to the depot. and a bit pedantically .... spelling for the signalling is SELTRAC. I believe the 4LM system will allow a slightly quicker re-entry process for non-communicating trains, which will certainly be useful particularly on the Met in the autumn. I wonder if the wheelslide/NCT design flaw that so badly affects JNUP will be eased or even designed out? Papers I have seen suggest LU has not been able to crack this challenge on JNUP despite a fair bit of work, and we thus appear condemned to pathetic brake rates in the open for the foreseeable future. I hope to be proved wrong on his. Back on the subject of the inductive cables, there have been a fair few incidents where trains have lost shoes thus wrecking the cable in the process. 95 and 96 stocks are rather prone to losing shoes. A good supply of doorstops for LU office accommodation if nothing else, although technically I suppose the 95 stock ones at least remain property of Alstom! A few find their way into people's equipment bags as a practical joke too, particularly at one depot. Yes, where the tags are 25m apart on 4LM the train only needs to pass over 2 tags in order to re-enter so it will be far quicker than JNUP.[/quote] A big improvement to the NCT issue would come from a software change to run trains on rear VOBCs all the time. This was implemented on the Jubilee and does make a difference. On the Northern the software change was requested but the money ran out. It is very frustrating that a big improvement can be delayed so much. It is (or was) due to come in with the next WTT when some other software changes are needed as well. The low brake rates are not sustainable if an improved headway is needed for NLU2 so sooner or later it will have to be fixed. Had I still been on 4LM I would have insisted on a lot of testing to understand how S stock would behave in a wheelslide situation ... hopefully the sanding will help. The resilience of the cable was rather overstated at the start of the project I think but it is certainly true that a lost shoe can cause a lot of damage to the cable. I remember investigating one such incident on the Jubilee at Neasden. To answer your question Basic difference is that instead of the red not orange loops in the 4 foot, we will use RFID tags and radio aerials to do the same job as JNP have suffered from breakages due to items being dropped onto it as it is fibre cable. We will still use axle counters where more precise train location is required I.e points or current speed control locations. Absolutely no link between axle counters and speed control locations or strictly speaking for precise location of communicating trains. The axle counters are for confirmation of point locking and tracking of unfitted or non communicating trains (NCTs). Precise train location for fitted trains comes from the VOBCs reading the tags on the track and between the tags from wheel rotations counted by the tachometers. At stations or other locations where extra confirmation is needed Seltrac allows for additional tags and, I think, on KCR in Hong Kong they have docking tags to confirm that the train doors are lined up with PEDS. |
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Post by Deleted on Mar 16, 2017 17:34:52 GMT
The reference to speed control was a guess as at Cannon Street they have installed axle counters yet to be commissioned though where they currently use position detectors in the speed control circuitry in signal A8400 and also in A840
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Post by Deleted on Mar 16, 2017 17:38:30 GMT
The reference to speed control was a guess as at Cannon Street they have installed axle counters yet to be commissioned though where they currently use position detectors in the speed control circuitry in signal A8400 and also in A840 Understood. The speed control in Seltrac comes entirely from the VCC based on it knowing the allowable track speeds, constraints, gradients etc. and the location of the train. It is always the VCC that issues speed instructions to the train. |
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Post by malcolmffc on Mar 16, 2017 22:05:35 GMT
What is the "NCT" issue and what is its impact?
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rincew1nd
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Post by rincew1nd on Mar 16, 2017 22:19:09 GMT
I *think* it's Non-Communicating Train, but happy to be proved wrong.
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Post by Deleted on Mar 16, 2017 22:20:05 GMT
What is the "NCT" issue and what is its impact? An NCT is a Non-Communicating Train. In brief, the TBTC system works like this. On board each train are two VOBCs (Vehicle on Board Controllers). Normally only one is active. Between the two running rails there are inductive loops, with crossovers every 25 metres. The VOBC can detect the change in the signal at these crossovers and can use this and other information to work out where it is. Using the inductive loop, the VOBC communicates with the VCC (Vehicle Control Centre) and tells the VCC where it is. Ideally all of the trains in the area under the VCC's control (there are multiple VCCs per line, with each having its own area of control) will be communicating with the VCC and telling it where they are. The VCC will use this information to calculate how fast a train can safely travel, work out when it needs to start braking and by how much and things like that. It will then communicate instructions to each train using the inductive loops. The VCCs also communicate with each other, obviously, to pass trains to each other, and with the Station Controller Subsystems (SCS), to command events such as point movements. Now if a train stops communicating with the VCC this is a big problem because it cannot then receive these instructions or provide updates to the VCC. It will therefore emergency brake and will have to be driven under the RM procedure (Restricted Manual - max speed about 17.5 kph) to the nearest point at which it can then re-enter the system. This point will be the next loop boundary. The inductive loops are a maximum length of 1 kilometre, and at the boundaries between loops, trains can re-enter the system. This will require the full length of the train to be clear of the boundary (marked by an EP (Entry Point) sign) in order that both VOBCs are fully in the next loop. This position is the clearance point, marked by an EPX sign. The RM procedure isn't a barrel of laughs as it obviously requires authorisation over any points between the train and the clearance point. |
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Post by Deleted on Mar 16, 2017 22:45:10 GMT
I *think* it's Non-Communicating Train, but happy to be proved wrong. The other meaning of a NCT is a Alien Train |
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Post by bananaman on Mar 17, 2017 5:28:48 GMT
How can an inductive loop be fibre optic? |
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Post by crusty54 on Mar 17, 2017 10:07:05 GMT
How can an inductive loop be fibre optic? not fibre optic - the cable is made with fragile fibres that are prone to damage in the hostile environment. |
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DWS
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Post by DWS on Mar 17, 2017 13:29:52 GMT
How can an inductive loop be fibre optic? The red inductive loop cable is a non fibre optic, staff on the Jubilee line at the time of the upgrade to the CBTC signalling had a 6 inch length of the cable posted to their home address at the time. Sill have mine some place and it has a single core wire in the centre of the insulation . |
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Post by trt on Mar 17, 2017 13:35:56 GMT
How can an inductive loop be fibre optic? I found some SelTrac documentation referring to it as The Fibre, but unless it's a combination fibre optic and leaky feeder / copper cable, I was wondering what witchcraft and devilry enabled Fibre Optic cable to be inductively coupled. |
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Post by Deleted on Sept 6, 2017 2:02:42 GMT
The first train has run in protected manual but using the tripcock as a back up ran from Goldhawk Road to Latimer Road using CBTC
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Post by MoreToJack on Sept 6, 2017 22:01:59 GMT
Thankfully I am on annual leave because this would make me very sad. Get that poxy ATC off my patch...! 😂ðŸ˜
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Post by superteacher on Sept 6, 2017 22:15:57 GMT
Thankfully I am on annual leave because this would make me very sad. Get that poxy ATC off my patch...! 😂😠You may come back to witness ATC domination! |
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Post by Deleted on Sept 6, 2017 22:35:03 GMT
Thankfully I am on annual leave because this would make me very sad. Get that poxy ATC off my patch...! 😂😠Well the normal conventional signalling don't work too good on your patch either  |
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Post by MoreToJack on Sept 7, 2017 0:10:25 GMT
Thankfully I am on annual leave because this would make me very sad. Get that poxy ATC off my patch...! 😂😠Well the normal conventional signalling don't work too good on your patch either Indeed. A110 and I are currently not friends...! |
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Post by MoreToJack on Sept 25, 2017 2:37:32 GMT
Thankfully I am on annual leave because this would make me very sad. Get that poxy ATC off my patch...! 😂😠You may come back to witness ATC domination! Close... but no cigar! Testing tonight saw a CBTC fitted train operate from the sidings into the platform under CBTC authorisation in RM... and then straight back into the depot. Oops. |
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Deleted
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Post by Deleted on Sept 25, 2017 2:58:23 GMT
Was that it  |
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Post by MoreToJack on Sept 25, 2017 3:10:33 GMT
Was that it The Future is operating with Severe Delays. |
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cso
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Post by cso on Sept 25, 2017 9:04:24 GMT
That doesn't sound much of a success then?
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Ben
fotopic... whats that?
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Post by Ben on Sept 25, 2017 13:55:26 GMT
When you redefine success, anything is possible.
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Post by zbang on Sept 25, 2017 17:23:39 GMT
The Future is operating with Severe Delays. That would make an excellent signature line, I may steal, err, re-purpose, it. |
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Post by 100andthirty on Sept 25, 2017 19:14:03 GMT
MoreToJack said "Testing tonight saw a CBTC fitted train operate from the sidings into the platform under CBTC authorisation in RM... and then straight back into the depot."
Do you mean PM? The whole point of RM is that no authorisation is needed (or indeed makes any difference how the train responds)
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