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TRTS RA CD Train Dispatch
#1
I have been asked to post something for someone unable to do so:
[I think because the software takes an objection to the "forward slash" character (unless it is separated by other letters by a space!) in the same way as it disallows the "percentage sign"]

Does anybody have any idea of the operation of TRTS CD RA plungers
and Indicators.
I am more concerned of the operating sequence, like which plunger is
operated first and the indication that appears first.

Any response is most appreciated.


TRTS= Train ready To Start. Operated by platform despatch staff (or when leaving depots / sidings by the shunter or driver).
Provided the relevant platform track(s) occupied causes an indication (generally blue flashing light) to illuminate on panel / VDU so that signaller's attention is drawn to it and knows that if they set the route that the train ought to be ready to leave (i.e. train crew on board, no expected station delays with disabled / luggage / large groups etc)- hence provoked to set route and commit the station throat pointwork for that train movement. Also used as an input to Automatic Route Setting. Indication continues until signal aspect actually clears.

CD= Closed Door. Indicates as auxiliary indication on signal itself and may be at several places along length of platform. Tells driver that station duties complete and should close the doors on power worked sliding door rolling stock. Driver learns that all doors have closed by the in cab door interlock light illuminating. Officially does not need to be interlocked with the signalling, but generally provided as part of the signalling system and then would generally prove that the signal is showing a proceed aspect (including PL) before it can illuminate.

RA-= Right Away. This is operated by platform staff to authorise train to leave- confirming that no one on the platform has clothing caught in the doors, no one fell down gap between train and platform on curved track etc. Replaces the traditional waving of green flag and blowing whistle by guard.
Generally provided in the same housing as the CDs, so the CD is extinguished once the RA lights. To avoid the hazard of driver failing to check signal aspect once provoked to depart by platform staff, the RA is interlocked- it can only illuminate if signal is off.


The TRTS is not safety critical and therefore generally plunger operated.

The CD is arguably, and the RA definitely is, safety critical so they are operated by key-switch and there is sequential proving to ensure that the switch is operated and released, so there needs to be a positive action to cause the indicators to illuminate.
PJW
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#2
Hi,

Thanks a lot for the detailed explanation.

I have a small query in the part which you have explained.
Does the Platform staff operate the CD Key Switch which is on the Platform first before the Driver operates the one which is on the train? If so, are there 2 opearations need to be done for CD, like one by the Platform staff and the other by the Driver on the Train.
Also to opearate CD, Signal should be cleared and if the Signal is not visible to Platform staff, do they operate the CD switch by observing the "OFF" Indicators which are present and lit on the platform once the signal is cleared.

Please correct me if am wrong.

Regards,
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#3
The CD switch on the platform causes the illumination of the CD indicatotrs which then inform the driver to close the doors; the driver therefore operates the control actually to implement this function.
Hence yes there are in a sense two operations, but only one associated with the CD indicator.

On automatic railways, it is actually often left to the driver / train captain to close the doors even though all other operations entirely automated. However there are railways which are truly fully automatic with no staff on the train and therefore the train dispatch has to be automated. I am not awre of any specific site, but it would not surprise me to find that on certain systems it could be an input from platform based staff that trigger the doors closing and subsequent departure. Otherwise if the platform has platform screen doors and /or some intrusion detection it would be possible to completely automate.

For the last part, indeed you are correct- the platform dispatch staff do need to check the signal aspect and this is generally the reasn why one or more OFF indicators are provided to enable them to do so from one of a number of reasonable positions along the length of the platform


(30-10-2012, 12:33 PM)jenni.joseph9 Wrote: Hi,

Thanks a lot for the detailed explanation.

I have a small query in the part which you have explained.
Does the Platform staff operate the CD Key Switch which is on the Platform first before the Driver operates the one which is on the train? If so, are there 2 opearations need to be done for CD, like one by the Platform staff and the other by the Driver on the Train.
Also to opearate CD, Signal should be cleared and if the Signal is not visible to Platform staff, do they operate the CD switch by observing the "OFF" Indicators which are present and lit on the platform once the signal is cleared.

Please correct me if am wrong.

Regards,
PJW
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#4
I would like to suggest a clarification. RA is defined as Route Available and not Right Away. Much of the above discussion is based on process which falls outside of the signalling system.

Platform staff and guards/conductors still use flags/lamps to communicate where the staff are available. There are many restrictions about how a train must be dispatched (read the Kings Cross incident on RAIB which describes the process and the failings in that instance). As PJw stated, the RA indication is interlocked with a proceed aspect. That doesn't detract that the platform staff and guard cannot try to dispatch a train without ensuring the signal is off.
Le coureur
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#5
According to the current rule book, RA Indicators are 'Right Away Indicators' however the signal the platform staff/guard are giving the driver is 'READY-TO-START'.

see http://www.rgsonline.co.uk/Rule_Book/Rul...ss%202.pdf

Whilst the rule book requires platform staff / guards to check the signal/off indicator before giving the ready to start signal, it is not an authority to move a train and the driver remains responsible for checking the signal is showing a proceed aspect before starting the train. Most trains have a Drivers Reminder Appliance (DRA) to reduce the chance of a driver forgetting to check the signal has cleared before starting the train, see http://www.rgsonline.co.uk/Rule_Book/Rul...ss%208.pdf for more details,
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#6
Part of my post is missing and I cannot seemingly add to it. So, I'll try to post one paragraph at a time...

The benefit of the CD and RA indications is to the DOO driver. They are not always able to look out of the cab and where they can, it may distract them from observing the signal's aspect - increasing the SPAD risk. If you observe where the CD and RA buttons are on a platform, they are not always in a position where the platform staff can see the front of the train - one of the requirement is that platform staff can see all doors from the dispatch point OR require further staff to enable them collectively to see all the doors. One of their checks is to ensure no-one is caught in the doors before giving "RA".

New Street is a good example where there is a mixture of crewed and DOO trains disptached from curved platforms as is London Bridge. It is worth reading the RAIB report referred to earlier and then watching the staff dispatch a train.

Arguably, these indications are not safety critical as they merely aid the driver.
* The platform staff should not try and dispatch the train without a proceed aspect.
* The driver should not try to move the train without the doors closed, the door proving indication lit and a proceed aspect.
* The CD indication is simply related to closing doors.
* RA is proved within the signalling system to not display unless a process aspect is given first, i.e. the signal is off.
* RA doesn't give the driver authority to move, the aspect does!

Discuss?
Le coureur
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#7
The aspect is a necessary but INSUFFICIENT condition. Also needs dispatch authority, whether this is given via RA indicator, a buzzer code from the guard or the old fashioned whistle and waving of the green flag.
None of these should be given unless the signal is off, but itis still the driver's responsibility to check.

(15-11-2012, 01:59 PM)Jerry1237 Wrote: * RA doesn't give the driver authority to move, the aspect does!

Discuss?
PJW
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#8
In response to Jerry's post, I would suggest that both CD and RA are potentially of benefit to all trains (DOO and non DOO). The rule book covers this as it allows platform staff to give the 'Ready To Start' signal to the guard using a CD indicator
At some stations (e.g. Manchester Piccadilly), the aspect is not always visible to the driver (particularly for short trains near the buffer stops) so the RA (although at Manchester the indicators actually display an 'R') is used by drivers to move towards the signal, as PJW states the driver needs a 'ready to start' signal and the signal off.

The rule book contains various methods of dispatching trains and I would encourage anyone interested to observe trains being dispatched from various stations. Just remember what you see actually happening isn't always correct. I have seen platform staff ask guards to look out of the window on the other side of the train to see if the signal is off, before giving the guard the signal to close the doors (OFF indicators have subsequently been provided as this is clearly not correct). I have also seen platform staff dispatch a train from a bay platform using the route indicator being displayed rather than the signal showing an OFF aspect (as route indicator was visible from where platform staff stood but the aspect itself wasn't). I won't name the station, but the dispatch arrangements have now been changed for that platform so the doors are opened on the other side of the train as the bay platform line has platform faces on both sides of the line, unfortunately the platform canopies only cover the side of the train the doors used to be opened on and they don't cover the side of the train the doors are now operated on so passengers now get wet when it is raining - all due to the arrangements for dispatching trains!

Also worth noting this subject is particularly topical this week : http://www.bbc.co.uk/news/uk-england-mer...e-20339630
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#9
(16-11-2012, 12:00 AM)mlupton Wrote: Also worth noting this subject is particularly topical this week : http://www.bbc.co.uk/news/uk-england-mer...e-20339630

Isn't it perculiar that the guard gets five years, the family are blaming him (and their culpability under the law), yet their daughter was five times the drink driving limit, breached numerous railway bylaws, was out at 23:30 and just 16! Seems a rather harsh sentence.
Le coureur
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#10
(19-11-2012, 09:40 AM)Jerry1237 Wrote:
(16-11-2012, 12:00 AM)mlupton Wrote: Also worth noting this subject is particularly topical this week : http://www.bbc.co.uk/news/uk-england-mer...e-20339630

Isn't it peculiar that the guard gets five years, the family are blaming him (and their culpability under the law), yet their daughter was five times the drink driving limit, breached numerous railway bylaws, was out at 23:30 and just 16! Seems a rather harsh sentence.

Apparently the girl got out of the train mistakenly before her stop when travelling back after party with her friends. I think they also morally have some responsibility as they evidently didn't prevent her leaving at they may have known was not her stop. Mind you they might also have been "worse for wear".
The Metro free paper had a letter this morning from someone who signed themselves "guard" warning of delays as he will in future will not be giving the RA when any member of the public is close to the side of a train.....
PJW
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