How do Northern's CAF units know which side the platform is on?

[kc_]

Shortly before arrival into a station, Northern's CAF units sometimes announce "door will open on the left/right". It's hit and miss though, which suggests entered by driver/guard or possibly just that Northern are having teething issues with it.

At a guess, the PIS knows the headcode and pulls platform number information with the ETAs for each stop.

Anyone know how it works?

 

[D365]

Is this the first time that this kind of announcement has been bought into use in the UK? I'm familiar with the system in Germany but haven't heard it on *National Rail before.

 

[FOH]

It's normal on the Jubilee and Victoria lines

 

[PG]

Back in the days of the slammers it was a case of lowering the window as the train drew into a station and swapping sides if you didn't see the platform on that side.

I suppose it was always possible that someone could have attempted to alight on the wrong side.

Question for any guards reading this -
If a passenger did tumble out wrong side would you have known before giving the Right Away?
i.e. was there a requirement to check the non-platform side?

 

[themiller]

Beacons like this one at Carlisle tell the train which platform it's on and which end (for through platforms).

 

[iknowyeah]

System called ASDO. Works off GPS and the headcode, so sometimes gets the platform wrong after a last minute change. Guards have to override it regularly by all accounts

 

[a_c_skinner]

If there are lots of beacons like the one illustrated I find it difficult to understand why the ASDO simply doesn't work properly.

 

[Neptune]

Back in the days of the slammers it was a case of lowering the window as the train drew into a station and swapping sides if you didn't see the platform on that side.

I suppose it was always possible that someone could have attempted to alight on the wrong side.

Question for any guards reading this -
If a passenger did tumble out wrong side would you have known before giving the Right Away?
i.e. was there a requirement to check the non-platform side?

I worked slam door EMU’s around Leeds. We never had to check the offside. However when arriving at a terminus station (Leeds, Ilkley, Skipton, Forster Square or Doncaster) or got put in P2 at Shipley when heading towards Leeds or P3 when heading towards Forster Square, we were instructed to announce which side the platform would be on along with the standard “do not open the doors until the train has come to a complete stand at the platform”.

 

[Neptune]

With regards the 195/331 knowing which side the platform is on its GPS based. Just not overly reliable yet.

 

[deltic14]

I'll second that and took a photo inside a 195 as it arrived at Hebden Bridge on its way to Leeds. The correct one was the one pointing to the left. I pointed this out to the guard who duly made a note in the fault book.

 

[jonnyfan]

The PIS gets the platform information from the ASDO system to show which side the doors will open on. The issue is, sometimes the PIS displays the door opening information before it has received the information from ASDO - so sometimes it is wrong and then corrects itself once ASDO provides the correct info. When the train approaches multi platform stations, then the PIS should show blank as ASDO won't know which platform the train will arrive in to until the guard overrides the doors to release them on the relevant side.

 

[Llama]

System called ASDO. Works off GPS and the headcode, so sometimes gets the platform wrong after a last minute change. Guards have to override it regularly by all accounts

Asdo doesn't work by headcode, you're thinking of the PIS for that, the systems are linked but separate - Asdo works fine if no headcode is provided in the PIS, and the PIS works fine if Asdo isn't working (but the PIS wouldn't display platform side info on approach to stations).

Asdo works by GPS and odometry. If it's guaranteed which side the platform will be on (eg in general terms a two-track station with a unidirectional pair of lines) then Asdo will know where it is and will send info to the PIS (which also knows where it is but independently and more loosely) which should display the side the platforms will open and remove the 'door not in use' roundels.

If the station in question is say bidirectional (eg Preston, Leeds) or a terminus (Liverpool Lime Street) then Asdo should know where it is if it is working correctly, but not which platform it will arrive at, so it can't show the platform side on approach and the guard must override Asdo by using SDO on arrival to open the train doors. Only once the train doors have been released in those circumstances will the PIS screens display the platform side. If Asdo isn't working correctly then the guard must check what kind of Asdo fault it is with the driver, report the circumstances and may have to use SDO, which bypasses Asdo, at every station.

Asdo works completely independent of beacons, the one pictured upthread is for TPE.

* edited first para to make it clearer Asdo doesn't use headcodes and PIS doesn't know itself which side doors are to be operated on.

 

[fulmar]

Deleted. LLama's post already explains it.

 

[bengley]

View attachment 72908 Beacons like this one at Carlisle tell the train which platform it's on and which end (for through platforms).

These beacons are only for class 185 CASDO (Coach based Automatic SDO)

As far as I'm aware there are currently no beacons for the 195/331 fleet though am willing to be corrected if this has changed!

 

[Llama]

It hasn't, the whole premise of the ASDO system is that it doesn't need beacons. Northern are resolutely sticking to that principle but in my opinion it will never work properly everywhere or be reliable enough in operation.

 

[Goldfish62]

It hasn't, the whole premise of the ASDO system is that it doesn't need beacons. Northern are resolutely sticking to that principle but in my opinion it will never work properly everywhere or be reliable enough in operation.

The system used by Southern on its Electrostars is GPS based and after some initial teething problems settled down very well.

 

[Llama]

Yes I am aware that there are similar systems that work reliably, but I suspect that this system is subtly different enough that it won't be able to be relied upon. There are a lot of teething problems with it losing its location which is predominantly odometry based (try saying that after a few pints!) - it can't use GPS in tunnels, cuttings etc but so long as it has its odometry location it is fine. But if it loses its odometry location (say severe low adhesion under braking) then even if it has a perfect GPS signal it won't let the Asdo work as GPS isn't fail-safe.

 

[Meerkat]

That sounds bonkers - why not just use balises so the guard has less to worry about?

 

[Goldfish62]

Yes I am aware that there are similar systems that work reliably, but I suspect that this system is subtly different enough that it won't be able to be relied upon. There are a lot of teething problems with it losing its location which is predominantly odometry based (try saying that after a few pints!) - it can't use GPS in tunnels, cuttings etc but so long as it has its odometry location it is fine. But if it loses its odometry location (say severe low adhesion under braking) then even if it has a perfect GPS signal it won't let the Asdo work as GPS isn't fail-safe.

That sounds very similar to what happened on Southern initially. It used to take ages for the doors to be released at Victoria due to the loss of the GPS signal. However, this was eventually overcome.

 

[Llama]

That sounds bonkers - why not just use balises so the guard has less to worry about?

Cost - the figures I've been told for balises from a Northern manager directly involved with Asdo in its current inception, and therefore likely to be biased towards the 'GPS rather than balises' approach, are along the lines of £4k per balise. This, if accurate, was claimed to be the whole cost including planning, possession arrangements and actually fitting the thing to a sleeper. A fairly simple station like Manchester Victoria would need ten balises.

In my opinion a balise based system should be simpler in operation and more failsafe than relying on rolling stock to know its location. The cost since introduction of the CAF trains cancelled or delayed due to issues with the Asdo system as it is, as well as the extra training required on its use, must now be approaching that which the relatively one-off cost of fitting balises would've been. This of course assumes such a balise system worked perfectly from day 1 though.

 

[SteveM70]

Asdo works by GPS and odometry. If it's guaranteed which side the platform will be on (eg in general terms a two-track station with a unidirectional pair of lines) then Asdo will know where it is and will send info to the PIS (which also knows where it is but independently and more loosely) which should display the side the platforms will open and remove the 'door not in use' roundels.

If that’s the case, how can a train arriving at Hebden Bridge from the west have the PIS say platforms are on the right?

 

[Llama]

The only answer to that is 'CAF'. On the picture posted above the PIS can't decide for itself, someone offered an explanation which sounds plausible but these units do things they shouldn't all the time - how many reports have there been of the PIS spuriously announcing "this train is too long for the next station, all passengers must move forward" or words to that effect on say a three car train at platforms it can easily fit on. When I've heard it through the cab door do that announcement on my train I know (because I've checked) that Asdo is still working fine and releases the correct number of doors, so it's clearly a PIS issue. There are a lot of bugs in the software of certain systems on these units.

 

[43096]

we were instructed to announce which side the platform would be on along with the standard “do not open the doors until the train has come to a complete stand at the platform”.

If someone could explain how a train could come to a partial stand at the platform, I'd be interested to know. It's either stopped or it hasn't, so use of the "complete stand" or "full and final stop" is a pointless addition.

 

[hwl]

The system used by Southern on its Electrostars is GPS based and after some initial teething problems settled down very well.

Most of the teething problems were sorted by fitting track balises in all the problem locations so while initially it was GPS only it has been GPS + balise for 14 /15 years.
Southern retrofitted Hima -Sella's tracklink2 rfid balise based system. Tracklink3 was used on Thameslink for 377/387s and SWT Windsor line etc retrofits, the 700s and newer installations should be using ETCS balises to a common standard as it is dirt cheap if the stock happens to be fitted with ETCS antenna and some othe r equipment fitted (e.g. Desiro City, Aventra and IET)

 

[Llama]

If someone could explain how a train could come to a partial stand at the platform, I'd be interested to know. It's either stopped or it hasn't, so use of the "complete stand" or "full and final stop" is a pointless addition.

Believe it or not, CAF units have the capability of thinking they've not come to a stand when they clearly have. This would prevent the train doors being released. There's a 'zero speed isolation' sealed switch in the cab for the driver to use when this happens which will allow the doors to be worked. This is pretty much the last resort in fault finding if the doors can't be made to play nice.

But yes, it's a phrase that's up there with 'final destination'.

 

[a_c_skinner]

As I've said before why is there not a national system debugged and working by now?

 

[Llama]

Similar reason as to why every new traction unit seemingly has a different coupler, or even a different orientation of the same coupler, leading to stranded trains several times a year. Too many commercial interests to keep standards linear.

 

[M1544]

I was on a 195 yesterday and I was travelling forwards and faced the screen that faced me when travelling forward to direction of travel And it said doors will open on left at Low Moor, which was correct. However the screen facing backwards to direction of travel (when I swung my head round) said doors would also open on the left, which was clearly wrong as for passengers facing that screen ie sat backwards the exit was on the right!. So the system is sending the same message to the screens without thinking which way the screens are installed in the carriages which effectively messes up the message being given.

 

[Skie]

If there are lots of beacons like the one illustrated I find it difficult to understand why the ASDO simply doesn't work properly.

Because the companies selling the systems that use GPS for this sort of thing make false claims about accuracy vs cost of putting beacons everywhere. GPS is never going to be accurate enough for this purpose, only beacons or something on the train using a camera and modern machine learning systems. But because beacons and maintenance are costly, cheap and unreliable alternatives are used.

Will probably take an incident to focus minds, sadly.

 

[hwl]

As I've said before why is there not a national system debugged and working by now?

Effectively there is, just CAF / Northern haven't followed it. Why not is the real question.
RIS 2747 RST.
As I said above for new NR installations it should be ETCS balise based. Most legacy installations on Southern, Thameslink, SWR and LU are Hima-Sella tracklinkII or III based.