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Post by astock5000 on Aug 4, 2008 17:43:46 GMT
There is a sign at Stanmore at the end of the platforms. It says 'Check VOBC' and looks like the DFA signs at Cannons Park ans Kingsbury. What does this sign mean?
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Tom
Administrator
Signalfel?
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Post by Tom on Aug 4, 2008 19:05:46 GMT
VOBC stands for Vehicle On Board Computer - it's a Seltrac thing.
Must be something to do with the dual fitting of new and old signalling on that stretch.
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Post by tubeprune on Aug 4, 2008 21:31:00 GMT
I would assume it is intended to remind T/Os to check that both VOBCs are working before they try to start the train. The VOBC is the computer which controls the train under ATC. There is one in each cab and they both have to be working to operate the train in service.
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Post by d7666 on Aug 5, 2008 16:40:59 GMT
I would assume it is intended to remind T/Os to check that both VOBCs are working before they try to start the train. The VOBC is the computer which controls the train under ATC. There is one in each cab and they both have to be working to operate the train in service. Both VOBC are not needed; trains may run in service in TBTC mode on only one VOBC - its designed that way - fully redundant processors.  I've just spent the last 2 days monitoring the DFA VCC at Neasden SCC -- Nick |
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mrfs42
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Big Hair Day
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Post by mrfs42 on Aug 5, 2008 17:38:12 GMT
And what does DFA VCC mean, please?  |
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Post by d7666 on Aug 5, 2008 19:33:00 GMT
Sorry, too many TLA that I use daily.
DFA = Dual Fit Area = (for practical purposes) Kingsbury to Canons Park = the area where a form of TBTC is fitted for trial purposes.
VCC = Vehicle Command Centre officially although many refer to it as Vehicle Command Computer. This is the central system processor - located at Neasden. DFA runs with VCC5 - there will be five VCC controlling the final set up, numbered east to west VCC1-VCC5.
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Nick
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mrfs42
71E25683904T 172E6538094T
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Post by mrfs42 on Aug 5, 2008 19:43:39 GMT
Cheers, that's what I *thought* it meant.  |
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Deleted
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Post by Deleted on Aug 5, 2008 21:39:20 GMT
I would assume it is intended to remind T/Os to check that both VOBCs are working before they try to start the train. The VOBC is the computer which controls the train under ATC. There is one in each cab and they both have to be working to operate the train in service. Both VOBC are not needed; trains may run in service in TBTC mode on only one VOBC - its designed that way - fully redundant processors. I've just spent the last 2 days monitoring the DFA VCC at Neasden SCC -- Nick That is sort of correct...... As far as I'm aware, you will need both VOBC's working when leaving the depot or sidings for the first time. If only one is working when a brake test etc is done then the train remains out of passenger service. Once in passenger service and only one VOBC is working then the train is to remain in passenger service with a changeover done asap. Please correct me if I'm wrong. |
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Post by d7666 on Aug 6, 2008 8:43:37 GMT
You may be right; I'm not involved with what happens ex-depot.
Although AFAIW if VOBC failed, unit remains in traffic, it simply does not change to PM but runs tripcock mode in DFA.
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Nick
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Post by tubeprune on Aug 6, 2008 9:28:06 GMT
Instructions to T/Os currently state:
"Trains CANNOT enter service with only 1 VOBC communicating."
If the active VOBCs fails, the train will get an emergency brake application until the passive VOBC wakes up and takes control. This may take a couple of seconds.
The T/O can try to reset the halted VOBC using the reset button in the cab.
Curiously, the instructions do not state positively that the train can remain in service. However, the implication is that it can but, in view of the above, one would imagine that the T/O would ask for a changeover.
Perhaps a change to the instructions is required to clarify this point.
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DWS
every second count's
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Post by DWS on Aug 7, 2008 14:59:38 GMT
VOBC stands for Vehicle On Board Computer - it's a Seltrac thing. Must be something to do with the dual fitting of new and old signalling on that stretch. VOBCs = Vehicle On Board Controllers |
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DWS
every second count's
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Post by DWS on Aug 7, 2008 15:02:18 GMT
Sorry, too many TLA that I use daily. DFA = Dual Fit Area = (for practical purposes) Kingsbury to Canons Park = the area where a form of TBTC is fitted for trial purposes. VCC = Vehicle Command Centre officially although many refer to it as Vehicle Command Computer. This is the central system processor - located at Neasden. DFA runs with VCC5 - there will be five VCC controlling the final set up, numbered east to west VCC1-VCC5. -- Nick VCC = Vehicle Control Centre SMC = System Management Centre |
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Post by d7666 on Aug 7, 2008 19:48:41 GMT
Curiously, the instructions do not state positively that the train can remain in service. However, the implication is that it can but, in view of the above, one would imagine that the T/O would ask for a changeover. Interesting. I do monitoring from VCC/SMC. As far as I am aware a failed VOBC train simply continues in (or reverts to) tripcock mode instead of Protected Manual. Of course, this is something that can only be done with DFA. In full TBTC there will be no revert to tripcock possibility - and I'd more or less agree then about changeovers. -- Nick |
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Post by d7666 on Aug 7, 2008 19:52:51 GMT
VCC = Vehicle Control Centre SMC = System Management Centre Depending on which engineering document you read, the first and second ''C'' of VCC may be found written as ''Control'' or ''Command'' and ''Computer'' or ''Centre'' which results in 4 permutations. And you may also find it as ''Centre'' or ''Center''. I've found its easier to just say VCC  -- Nick |
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Post by d7666 on Aug 7, 2008 21:07:23 GMT
Depending on which engineering document you read, the first and second ''C'' of VCC may be found written as ''Control'' or ''Command'' and ''Computer'' or ''Centre'' which results in 4 permutations. And you may also find it as ''Centre'' or ''Center''. Sorry, there more, had to leave computer earlier before typing all i wanted to say. AIUI variations in VCC meaning comes from some earlier installations that were much simpler with only one VCC, and in other parts of the world where different terminolgy is ised. In a single VCC installation, the last C means Centre instead of Computer - its in practical terms the same thing - the [single] computer at the control centre. AIUI the first C meaning Command or Control seems to come from other parts of the worls where some metros have ''command centres'' rather than ''control rooms''. Again it all ends up meaning the same thing. Same sort of thing accounts for variations in what the C in SMC means. -- Nick |
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I've just spent the last 2 days monitoring the DFA VCC at Neasden SCC 
