TBTC Testing

[Deleted]

Feb 22, 2011 13:49:44 GMT North End said:

This is nothing new, on most lines the T/Op can judge how close the train in front is due to the numbers of people on the platform, and the dot-matrix gives an indication of the gap behind.

As I've said before, a decent Train Operator can do everything ATO can do.

I'm sympathetic to the sentiment but in many ways the line is only as fast as its slowest driver/train and you're never going to get a depot full of 'decent' train operators. And as much as I'd rather ATO wasn't a reality, for a whole bunch of reasons, even I wouldn't claim that we can ever drive a train as precisely close to the next one as a computer.

Nevertheless I sometimes wish I could elect to drive the train manually at times. You could still run a significantly improved moving-block signalling system with manual driving. Driving the train in 'protected manual' (as we did for a few days after Christmas) was actually quite headache-inducing due to the frequent alarms and sounds and the sheer frustration of being required to adhere to crude, unexpected, speed changes and funereal entrances to the platform. But I'm sure some of those problems could be addressed with a bit of ingenuity and imagination.

I do realise I'm in cloudcuckoo land but I wish it was realised that, for all the potential advantages of ATO, there is a trade-off when staff become generally less skilled or less occupied. With the best will in the world, you cannot help but be less alert and 'switched-on' when the train is driving itself and perhaps a little less prepared to deal with problems when they occur.

I often hear it said that we're paid for what we know rather than what we do but the train op job is undoubtedly becoming dumbed down on the jubilee - the annual stock training is becoming virtually non-existent. These are worrying times.

[Deleted]

Feb 22, 2011 18:54:22 GMT @cj said:

Andrew, you seem to forget the tripcock system. Or moving block ATP which is the safest as it doesn't rely on fixed length overlaps!

Well, yes. True.

Somehow, the Waterfall crash seems to have bypassed the trip system...

[Deleted]

Feb 23, 2011 9:45:28 GMT @axewielder said:

Feb 22, 2011 18:54:22 GMT @cj said:

Andrew, you seem to forget the tripcock system. Or moving block ATP which is the safest as it doesn't rely on fixed length overlaps!

Well, yes. True.

Somehow, the Waterfall crash seems to have bypassed the trip system...

There wasn't one...

[Deleted]

Feb 23, 2011 9:50:14 GMT @cj said:

Feb 23, 2011 9:45:28 GMT @axewielder said:

Well, yes. True.

Somehow, the Waterfall crash seems to have bypassed the trip system...

There wasn't one...

Well that explains it.

*walks off feeling like an idiot*

EDIT: Wait, now I feel really secure at the idea of taking CityRail.

[Chris M]

Feb 22, 2011 18:54:22 GMT @cj said:

Andrew, you seem to forget the tripcock system. Or moving block ATP which is the safest as it doesn't rely on fixed length overlaps!

But LU's implementation of ATO doesn't use tripcocks.

[Deleted]

Feb 23, 2011 11:46:17 GMT Chris M said:

Feb 22, 2011 18:54:22 GMT @cj said:

Andrew, you seem to forget the tripcock system. Or moving block ATP which is the safest as it doesn't rely on fixed length overlaps!

But LU's implementation of ATO doesn't use tripcocks.

Yes, I am fully aware that ATP/ATO in the classic sense uses coded track circuits and TBTC using a loop! Not silly! Tripcocks was referring to prevention of unintentional inter-train contact...

[tubeprune]

Yesterday, there was another sit-down on the Jubilee due to a TBTC problem. It seems to have been made worse by a further problem described as "a hidden conflict avoidance zone ahead". Does anyone know what this is?

[mrfs42]

My only guess (and I'm really clutching at straws here) is some form of flank protection.

Conditional flank protection at that!

[Deleted]

Not sure about the 'hidden' bit (they are normally visible on the control centre signal displays), but all Seltrac TBTC implementations have conflict avoidance zones (known as a CAZ). All these really are is a kind of route locking / reservation designed for junctions where mutliple trains could get routed into a conflict or standoff situation. To avoid that, one train reserves the CAZ area and then nothing else can go there until that train has gone through the area.

[frankoids]

Feb 23, 2011 1:59:29 GMT @tubbytube said:

[quote author=brbclass465 board=jubilee I'm sympathetic to the sentiment but in many ways the line is only as fast as its slowest driver/train and you're never going to get a depot full of 'decent' train operators. And as much as I'd rather ATO wasn't a reality, for a whole bunch of reasons, even I wouldn't claim that we can ever drive a train as precisely close to the next one as a computer.

I do realise I'm in cloudcuckoo land but I wish it was realised that, for all the potential advantages of ATO, there is a trade-off when staff become generally less skilled or less occupied. With the best will in the world, you cannot help but be less alert and 'switched-on' when the train is driving itself and perhaps a little less prepared to deal with problems when they occur.

I often hear it said that we're paid for what we know rather than what we do but the train op job is undoubtedly becoming dumbed down on the jubilee - the annual stock training is becoming virtually non-existent. These are worrying times.

I agree and the problem about being less alert and switched in a semi computer controlled system is a well known one in aviation. When the s*** hits the fan and the computer 'gives up' the pilot is left with a virtually un-recoverable situation flying wise and in totally the wrong mental state to deal with it.

[Deleted]

Saw a problem today at Dollis Hill. The TBTC signal aspect kept switing from red to red and blue constantly for about 3 minutes, the trainstop also raising and lowering at the same time as the aspects were changing. Anyone know what caused this?

[Deleted]

Feb 25, 2011 22:46:21 GMT @bronzeonion said:

Saw a problem today at Dollis Hill. The TBTC signal aspect kept switing from red to red and blue constantly for about 3 minutes, the trainstop also raising and lowering at the same time as the aspects were changing. Anyone know what caused this?

That would be a communications cockup...

[jardine01]

Does anybody know if all the Jubilee line trains are now running in ATO or is there still some trains running in Manual mode?

[Deleted]

I believe all of them are now driving automatically south (or east if you want) of Dollis Hill. Dollis Hill-Stanmore is still manual. Or am I mistaken as usual?

[causton]

Feb 26, 2011 18:50:33 GMT @eirikho said:

I believe all of them are now driving automatically south (or east if you want) of Dollis Hill. Dollis Hill-Stanmore is still manual. Or am I mistaken as usual?

That was what I saw posted on the Service information board (for drivers just past the swing-gate) at Kingsbury on Monday, so I assume it is true

[Deleted]

Another naff (good!) service on the Jubilee, noted at 13.00 at Canning Town WB -

1 WEMBLEY PARK 16 mins
JUBILEE - GOOD SERVICE

Of course it was(n't)

[Deleted]

If it interests anyone and I apologise if it hasn't been mentioned before but in France, all metro lines apart from line 10 *can* be driven in ATO mode. This usually only happens in the rush hour but the driver has the choice to drive in manual or ATO outside these times. There are normal line side signals and speed limit signs to aid manual driving under full ATP.

Would this have been a better system to have in place so traditional manual driving can take place? I'm still unsure if Jubilee/Central line drivers can drive in protected manual outside of peak times (or is only Sunday mornings) ?

The RER line A uses in cab signalling in the central section under the city but it is ATP and not ATO and from what i've seen of it seems to be quite easy to drive to with a large display indicating to the driver what speed is permitted - similar to the TVM systems used on LGV high speed lines.

[plasmid]

Central can drive in full manual during peak during the strictly-only ATO section.

After being held at Stratford for 5 minutes because of a PEA at Mile End, the driver proceeded manually to Mile End and then ATO thereafter this morning.

[Deleted]

I would imagine it is easier (or should I say more predicatable) to drive in ATP on the Central than it is in the PM mode of TBTC on the Jub, purely because the speed codes of the Central are more rigid in the way they work, and there are still lineside signals giving an overall clue of what to expect - Green (unrestricted run to next signal - i.e. totally predicatable), White (also likely to be unrestricted, but driver would be half expecting a drop in target speed along the way), and red. TBTC can give you any target speed and many more varied target points, making it much more difficult to drive with confidence to the display as it can change pretty radpidly.
Is it not still true that typically one or two trains on the central are always running around in ATP mode because of faulty ATO controllers? From what I have experienced a train in ATP on the Central seems to be able to keep to time much better than a PM train on the Jubilee.

[Deleted]

Lines 3b and 7b in Paris are manual driving too.

[Deleted]

Mar 2, 2011 21:58:53 GMT @sw206 said:

I would imagine it is easier (or should I say more predicatable) to drive in ATP on the Central than it is in the PM mode of TBTC on the Jub, purely because the speed codes of the Central are more rigid in the way they work, and there are still lineside signals giving an overall clue of what to expect - Green (unrestricted run to next signal - i.e. totally predicatable), White (also likely to be unrestricted, but driver would be half expecting a drop in target speed along the way), and red. TBTC can give you any target speed and many more varied target points, making it much more difficult to drive with confidence to the display as it can change pretty radpidly.
Is it not still true that typically one or two trains on the central are always running around in ATP mode because of faulty ATO controllers? From what I have experienced a train in ATP on the Central seems to be able to keep to time much better than a PM train on the Jubilee.

White means restricted speed code, proceed under ATP/ATO only.

Reason being, that the target speed for the next block is carried in the data for the current block as well.

[Deleted]

Mar 2, 2011 22:20:28 GMT @reganorak said:

Lines 3b and 7b in Paris are manual driving too.

oh right i forgot about them as they are so short!

[Deleted]

Mar 2, 2011 11:41:49 GMT @notatraindriver said:

If it interests anyone and I apologise if it hasn't been mentioned before but in France, all metro lines apart from line 10 *can* be driven in ATO mode. This usually only happens in the rush hour but the driver has the choice to drive in manual or ATO outside these times. There are normal line side signals and speed limit signs to aid manual driving under full ATP.

(...)

On the "metro" system in Paris (apart from lines nmr 3b, 7b and 10), ATO is always provided. But it can be switched off by any driver; and it is compulsory for every driver to drive manually at least a full "turn" (a full way round the line) every day. This requirement helps maintaining their ability to drive in case of a malfunction of the ATO system.

During automatic operation, the only manual action is -if necessary- to delay the doors closing process.

This does not apply to line nmr 14 wich is fully automated, without any driver, and will not apply either to line nmr 1 wich is currently being converted to full automation.

[Deleted]

Since we're on the topic of foreign metro systems, I'd like to mention the former Soviet Union. Many metro systems there have some kind of ATO, but the busiest one, in Moscow, does not. All trains are manually driven, with various forms of train protection ranging from the traditional train stops to various forms of coded track circuits. It's been found that driving the trains manually can get the best use of capacity, with 39 tph being the current peak service, though 40 tph timetables are occasionally tried. Headways are managed by simply putting a timer on the headwall of each station that says how long it's been since the last train departed, and this lets drivers know to speed up or slow down.

One notable thing for the ATP systems is how resistant to failure they are. The initial coded track circuit ATP retained full lineside signalling and train stops, so that a train with failed ATP could still run normally. A later version had the signals normally off and no trainstops, but this version, also had a feature, called the Independent Backup Device, where the codes were received by both the front and rear of the train, so that if the receiver on the front of the train failed, the one on the back could be used, albeit with some reduction in speed. And if that failed, or if a non-fitted train had to use the line, the lineside signals could be turned on, and the train could use those, though not in passenger service. The most advanced version has even more redundancy, with two sets of ATP equipment on each end of the train, so there's a pretty good chance that at least one of them will work, allowing the train to keep going in service, and if that fails, it can be taken out of service and run to the nearest siding using the lineside signals and a second person in the cab, at some reduced speed, which is something like 20 or 25 mph. When you have a 39 tph service, and 1.5-2 million passengers a day on your metro line, you really, really don't want trains to fail and tie up the service for any length of time.

It seems like this sort of robustness ought to have been a design goal for the system on the Jubilee Line, and the rest of the Tube too for that matter.

[jardine01]

Why could they not just have a moving block signaling system with Manual driving on the Jubilee?

[Deleted]

Mar 5, 2011 16:43:10 GMT @jardine01 said:

Why could they not just have a moving block signaling system with Manual driving on the Jubilee?

That feature is available.

[jardine01]

I see, but when will they be allowed to drive manually? is there certain times they can drive or on certain sections of the line? i would imagine most trains will operate in ATO most of the time i guess?

[Deleted]

I would hope it's at least a similar arrangement to the Central where open sections are allowed in PM; of course ATO doesn't like rain very much.

[Deleted]

All trains in ATO everywhere (Stratford to Dollis), unless 'out of service' when they are normally in PM mode is the current way of running the Jubilee as I understand.

[jardine01]

most trains now run in ATO yes, but i dont think they all are i went on one in Febuary and i am sure it was in PM mode.