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

Skie said:

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.

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Only certain naive manufacturers believe them though...

M1544 said:

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.

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Ive seen that occasionally, but most of the time the message is reversed for the screens facing backward facing seats

So we have:

- all screens correct
- all screens wrong
- front facing correct, rear facing wrong
- rear facing correct, front facing wrong

And screens on different trains behaving differently at the same station

It’s bloody useless, really. Thankfully passengers rely on looking out of the window

195s and 331s have ETCS receivers, although the system is at least partially disconnected - the ETCS screen in the cabs is just blank (as though no power to it) all the time. In 331s it seems to be the case that the ERTMS isolation switch is operated in the cab, on 195s it generally isn't but the screen is still dead.

M1544 said:

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.

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But surely that'd be confusing. Left ought to be meant in the direction of travel. On the tube, if 'right hand side' is announced but I were to get up and walk in the opposite direction to the direction of travel to the nearest door then my right is the trains left, (not sure how to word that better) surely the same principle would apply here.

Admittedly there is a problem since arrows are included on the PIS of these units so the arrow ends up pointing in the wrong direction. Slightly confusing problem to overcome.

iknowyeah said:

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

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More generally, some ASDO systems work off GPS, some off GPS and beacons, some others work off beacons only. It’s not really possible to generalise.

The beacon standardised “bit pattern” allows for information about correct side door enable, (CSDE), to be read by a train, but some train systems don’t respond to it yet. I think RSSB see beacons as the most accurate method?

swt_passenger said:

I think RSSB see beacons as the most accurate method?

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CAF aren’t exactly dissuading them!

As a side issue to the platform announcements every time I’m on a 195 and it approaches Bradford interchange, despite previously announcing that we would shortly be arriving Bradford as soon as it passes Mill Lane Jn on approach the PIS jumps forward and announces that we are now arriving at either Halifax or Low Moor depending on the trains next stop. Can only presume that the PIS can’t handle the fact it passes Mill Lane Jn twice outside Bradford - once in and once out. But passengers are often seen about to leap out of their seats thinking they have almost missed their stop. After almost 4 months in operation you’d think a fix would have been rolled out for this.

Llama said:

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.

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The CAF ASDO solution uses two means to identify the location of the train - GPS and Odometry. This provides a sound understanding of where the train is, and despite not being as watertight as beacons in the 4ft, it’s a very effective way to cover large areas of network quickly with a good level of failure protection. If either component fails or the two don’t agree, it throws up a fault on the TMS and a human has to intervene.

The ASDO GPS system works by using a series of 'beacons' - imagine these as huge invisible bubbles on the track that the train drives though. I'll use Rochdale as an example...

• The train runs from Manchester and just before Rochdale is an ASDO beacon. This tells the train that it is on the approach to Rochdale, allowing it to set a door release pattern in the TMS.
• At this point, it has no idea which platform it is in. It could be terminating in Platform 4 (doors to the left) or be continuing to Leeds via Platform 1 (doors to the right).
• The train stops in the platform and as all the platforms at Rochdale can accommodate the full length of the train, all doors are available, thus the 'Door Not In Use' lights are extinguished. The Guard keys in, releases the local/all doors.
• The Guard then closes the doors and the train pulls away.
• Shortly after leaving Rochdale, the train then hits another ASDO beacon, as the ASDO system has just received an entry to Rochdale, this is assumed as an 'exit' beacon, thus clearing the door release pattern.
• This same process applies to TPE systems, except the door release is given by the driver.

Now... the interesting part here is that the ASDO has not been used to locate which platform it has been on, nor which side is to be released, because it doesn't matter as it will fit on all platforms. Introduce a situation like Manchester Oxford Road with a Class 397 and it becomes more critical to know which platform you are on to ensure a correct door release pattern. This can be achieved by:

1. the driver selecting an option on the TMS to confirm platform; or,
2. adding a beacon into the 4ft that confirms the platform after the GPS locates the station; or,
3. failing safe and opening the minimum number of doors at all platforms.

Imagine you're on the approach to MCO, the ASDO system has located where you are, but it still doesn't know what platform you are in so all the doors say 'Not in use'. The train hits the beacon (or comes to a stand and is confirmed by the driver) and all of a sudden it knows, allowing the correct door release pattern and announcements/graphics to be triggered explaining that the last coach doesn't fit. The only problem with this is that you're in the station when it happens, which doesn't really allow enough time to get your things to the next coach without incurring delay. The only way to achieve this is to decouple the PIS from the ASDO and 'fail safe' by giving short-platform announcements in advance, regardless of platform, OR assume that unless the train is booked into a short-platform, there is no need to do any announcements. This interaction for short-platform information is exactly the same logic as knowing which side the doors will release on.

Northern's implementation is more complex and I must confess I do not have full understanding of their set-up. However, to know the correct-side, the train must know the platform it is routed through. At simple stations with a uni-directional Up/Down, ASDO has the potential to know which side of the train doors can be released on, this can then be fed to the PIS system when the train runs through a entry beacon and the correct number of doors on the correct side are armed/enabled. In theory, as long as the PIS database is correct, this should be seamless, as there will be no change when ASDO locates the station and updates the PIS (as in congested areas, this can be quite late). This works the same for short-platforms that differ on the up/down. In theory, you don't need the ASDO input in this scenario but it needs to work to enable the functionality at multi-platform stations...

At multi-platform stations, Northern's method of work introduces more challenge. Having door release by the Conductor (no doubt as a result of various RMT pressures over DCO) doesn't allow the system to be informed via the TMS when it can't identify the platform. You then have the potential to see the PIS database suggesting doors on one side (based on the booked platform) and the train being routed through a different one. When the Guard then overrides the ASDO (as they have no way to 'inform' it) to release the doors, the PIS is also advised.

It’s all about how the different systems talk to each other and pass information. Northern and TPE both have different implementations of the same kit and it seems that some of the set-up on the Northern units (with screens not knowing which way they face) requires some improvement. I've said it elsewhere that when glitches are noticed, it can be a while before a new software version is able to make it round to all units in the fleet so there is quite possibly some out of date units, hence the inconsistencies. IMO knowing which side of the train the doors will open on is negligible and I'd turn it off on Northern's units. TPE don't have it on for this very reason (as most stations called at have multiple platforms).

All this just to tell you what side the doors are opening on. Is this system really needed?

The 195/331s have the information programmed in for simple stations or in the case of Man Picc 13/14 trains towards the Airport have it programmed in for 13 and Liverpool bound 14. Any other platform would require over ride. At other multi platform stations the guard over rides as it doesnt know what platform as there is no agreement for drivers to input the platform into the ASDO system if they do get an agreement then ASDO would be used all the time during normal running instead of having to override at certain complicated stations

Having been on a 195 for the Chester - Leeds 10p extravaganza twice this week I was also confused at the auto announcements at Hebden Bridge and Bradford Interchange that the train was too long for the platform and that certain doors would not open - listen to announcements. It was only a three coach train both ways, all coaches did fit and there were no further announcements (!)

Ride quality is awful isn’t it!

The Prisoner said:

Having been on a 195 for the Chester - Leeds 10p extravaganza twice this week I was also confused at the auto announcements at Hebden Bridge and Bradford Interchange that the train was too long for the platform and that certain doors would not open - listen to announcements. It was only a three coach train both ways, all coaches did fit and there were no further announcements (!)

Ride quality is awful isn’t it!

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The short platform is totally random and it quite funny on a 331 at Wakefield Westgate at a 4 car wont fit on.
And theyre not the smoothest of trains especially with the braking system making a smooth stop tricky

Adam0984 said:

The short platform is totally random and it quite funny on a 331 at Wakefield Westgate at a 4 car wont fit on.
And theyre not the smoothest of trains especially with the braking system making a smooth stop tricky

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Is that because there is a short platform? Not necessarily the one your train used.

I saw a similar screen on a 331 on Saturday, proclaiming that we were about to arrive at Salford Crescent, when in fact we were just leaving Chorley.
It continued to say we were imminently arriving Salford Crescent, as we actually stopped at Horwich, Lostock & Bolton then after genuinely stopping at Salford Cresc, the screens caught up with reality, correctly announcing Deansgate (where I got off).
Luckily, it didn't announce which side to get off at, as all stations except for Cresc involved the left-hand doors.

Seeing all the above makes me grateful for the set up on SWR and the PIS the desiros currently use.

I’ve never know of any issues with the ASDO, all the hard work is done, even if it’s a last minute change of platform (Eastleigh 3 on the up!). The beacons can’t be THAT expensive as they’re fitted to every platform an SWR Desiro stops at, sometimes there’s one at each end if the platform is Bi-directional or SIMBIDS.

The only way I would improve it is to include CSDE (Guildford gully) and a beacon per coach so in the event of a stop short, the train would only release what is accommodated.

I hope the new system being planned for SWR isn’t as pony as the one above. Sorry for wandering off topic.

Adam0984 said:

The short platform is totally random and it quite funny on a 331 at Wakefield Westgate at a 4 car wont fit on.
And theyre not the smoothest of trains especially with the braking system making a smooth stop tricky

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The 'holding brake' which applies automatically below 1mph is far too aggressive on 331s, much more so than on 195s.

To avoid a sudden stop throwing people about on 331s you need to have 50-60% brake effort in as you stop, any less and the holding brake gives a very harsh sudden increase in brake force as it stops you.

On 195s 20% is enough to get the same effect, for some reason the holding brake applies with a lot less force on the 195s than on 331s.

It's not possible to get a smooth stop on either 195 or 331 like you can on other traction.

pompeyfan said:

Seeing all the above makes me grateful for the set up on SWR and the PIS the desiros currently use.

I’ve never know of any issues with the ASDO, all the hard work is done, even if it’s a last minute change of platform (Eastleigh 3 on the up!). The beacons can’t be THAT expensive as they’re fitted to every platform an SWR Desiro stops at, sometimes there’s one at each end if the platform is Bi-directional or SIMBIDS.

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They aren't expensive (10year fit and forget like a domestic smoke alarm, replace after 10 years) most of the cost is the installation work itself and paperwork!

The only way I would improve it is to include CSDE (Guildford gully) and a beacon per coach so in the event of a stop short, the train would only release what is accommodated.

I hope the new system being planned for SWR isn’t as pony as the one above. Sorry for wandering off topic.

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That isn't how the "proper" systems work though - they all rely on a decent amount of functionality /computing power in the TCMS and door systems (which Electrostars, Juniper (SWR 458), Desiro City (inc. SWR 707), Aventra (inc. SWR 701) and Movia (LU S stock)) have so everything is done on a train (not coach) basis so a full install for stop short/long, different train lengths and CSDE needs very few beacons - fewer than the number of coaches.

As the Desiros don't have individually addressable doors and less TCMS functionality (and ditto Turbostars on this later item) they don't get the full functionality of a proper system (the systems were originally designed for Electrostar so assume Electrostar level functionality as basis).

With 701s you should be expecting functionality on par with Thameslink 700s / LU SSR / London Overground / Crossrail (currently only GW side fully functional) not what Cheap As F. who now have the oldest current TCMS system design of any manufacturer have fitted...

tpjm said:

Is that because there is a short platform? Not necessarily the one your train used.

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No both platforms at Westgate are capable of taking a 10 car azuma so I'm sure my little 4 car should squeeze on

Idiotic said:

All this just to tell you what side the doors are opening on. Is this system really needed?

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I'm not sure to be honest why a much simpler physical beacon-based system is not used. It would be reliable and accurate. All it needs to tell the train is how many metres the platform is long on entering it, and have a second one to ensure the cab is in the right place.

hwl said:

They aren't expensive (10year fit and forget like a domestic smoke alarm, replace after 10 years) most of the cost is the installation work itself and paperwork!


That isn't how the "proper" systems work though - they all rely on a decent amount of functionality /computing power in the TCMS and door systems (which Electrostars, Juniper (SWR 458), Desiro City (inc. SWR 707), Aventra (inc. SWR 701) and Movia (LU S stock)) have so everything is done on a train (not coach) basis so a full install for stop short/long, different train lengths and CSDE needs very few beacons - fewer than the number of coaches.

As the Desiros don't have individually addressable doors and less TCMS functionality (and ditto Turbostars on this later item) they don't get the full functionality of a proper system (the systems were originally designed for Electrostar so assume Electrostar level functionality as basis).

With 701s you should be expecting functionality on par with Thameslink 700s / LU SSR / London Overground / Crossrail (currently only GW side fully functional) not what Cheap As F. who now have the oldest current TCMS system design of any manufacturer have fitted...

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thanks for the detailed reply. I mis-worded my post earlier in regards to how the beacon interacts with the classic desiro stock. If the TMS could handle it a receiver on each coach would be beneficial

Bletchleyite said:

I'm not sure to be honest why a much simpler physical beacon-based system is not used. It would be reliable and accurate. All it needs to tell the train is how many metres the platform is long on entering it, and have a second one to ensure the cab is in the right place.

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On entry the train looks up in the on board database the platforms length (and sometimes which side if the system has CSDE too) based on the balise ID. You then have a pair of balises for each set of car stop positions on the platform to create an "as planned" envelope for quick door opening and to deal with short / long stop situations in the first instance with odometry and additional readers used to sort the number of doors that should be opened if the train doesn't stop between the pair.

Can anybody explain the ‘correct external displays but NOT IN SERVICE internal displays’ issue?

Yes. This happens when the unit has been put into 'empty transportation' (ET) mode which is meant to dim the saloon lights, turn off the saloon HVAC and WiFi, and display 'not in service' inside and outside.

When you take the unit out of ET mode for some reason the 'not in service' sticks on the internal screens.