Selective Door Opening in the future?

[Hartington]

Selective Door Opening.

Forget current stock, this is a question about what might be feasible in the future.

For instance, suppose you have a route which has platforms (except at the terminii) that can only service two cars. With modern things like GPS and balises and the kind of passenger information systems that you find on Japanese trains what's to stop the railway running 3 car trains? You could stop the train with the front car off the platform and only open doors in the rear two then at the next stop leave the back car off the platform and only open the doors in the front two cars. If the cars had 1/3 - 2/3 doors you could even stop with the centre car centred on the platform and leave the front doors of the front car and the rear doors of the rear car closed. The PIS would show which doors would open at the next station. I say 3 car but the principle could be applied to almost any train length.

 

[Dstock7080]

You say forget current stock but LU S7 Stock already perform this, stopping 7-car trains in 6-car platforms, with various doors beyond the platform ends, without GPS.

 

[Nym]

And that the "new" signalling on the Jubilee and Northern Line supports end door lockout and SDO within the on train unit.

(As is used on the DLR)

 

[SeanG]

This happens at lots of locations across the country

 

[swt_passenger]

This happens at lots of locations across the country

It is not usual on main line trains to have SDO to individual door level, generally you'll get both or none of any individual carriage.

The 5 car LO 378s have the last functionality required by the original questioner now, for the short stations on the ELL. IIRC it might be the last set of doors in the trailing end of the unit only.

(Another scenario, where trains open only one door on a very short platform, is not SDO, but usually just the guard using the 'local door', aka LDO.)

 

[Cherry_Picker]

Am I right in thinking LM 350s and 172s already have this feature? There are plenty of SDO stop boards at smaller stations in the West Midlands.

 

[MCR247]

350s don't. They only have UDS - unit deselect

 

[NX]

Unit de select on the 350s just locks out the whole four cars, it's mainly used on the southern west coast stations like Bletchley.

NX

 

[Skoodle]

The 5 car LO 378s have the last functionality required by the original questioner now, for the short stations on the ELL. IIRC it might be the last set of doors in the trailing end of the unit only.

The 378s are being successfully retrofitted to enable SDO and Correct Side Door Enable. They use a combination of track beacons, GPS and distance monitoring. 2 of the 3 have to be successfully determined before it will release the doors. It is either the last set of doors in the rear carriage, or the entire rear carriage locked out.

 

[swt_passenger]

The 378s are being successfully retrofitted to enable SDO and Correct Side Door Enable. They use a combination of track beacons, GPS and distance monitoring. 2 of the 3 have to be successfully determined before it will release the doors. It is either the last set of doors in the rear carriage, or the entire rear carriage locked out.

Thanks for the extra detail, I suspect like the new SWT system it only 'measures' from the front of the train, I can't think of a scenario where you'd have the back of a train in the platform and keep the front set of doors or whole carriage closed, but I dare say the technology would appear if it was asked for.

As someone mentioned above, DLR can already deal with a train that overhangs a short platform at both ends, Cutty Sark isn't it?

 

[87015]

Thanks for the extra detail, I suspect like the new SWT system it only 'measures' from the front of the train, I can't think of a scenario where you'd have the back of a train in the platform and keep the front set of doors or whole carriage closed, but I dare say the technology would appear if it was asked for.

Canada Water turnarounds possibly? Crossover is south end, presuming signal is at end of platform the front end on arrival would need to overhang?

 

[swt_passenger]

Canada Water turnarounds possibly? Crossover is south end, presuming signal is at end of platform the front end on arrival would need to overhang?

Seems possible, perhaps someone knows exactly how it works there. An alternative would have been to resite the signal slightly if there was room.

 

[Skoodle]

The beacon to read the balise is in the PTOS, in the middle of the train. It retains the platform information for 200m. At Canada Water for the time being, if we crossover Northbound, to the Southbound platform, our stop board is in the tunnel and leaves the rear cab in the tunnel. We can only leave ECS if we are a 5 car train doing this shunt move. The other moves are not affected.

 

[ADRboy]

380's use SDO on the Ayrshire lines.

 

[Stew998]

Southern 377s have had this for a few years for stops where platforms will only accomodate 8 or 4 cars rather than 12 (eg Balcombe and a few smaller stations on the Eastbourne line).

 

[swt_passenger]

Southern 377s have had this for a few years for stops where platforms will only accomodate 8 or 4 cars rather than 12 (eg Balcombe and a few smaller stations on the Eastbourne line).

Southern's SDO system (on the 377s) can select to individual carriage level, not just 4 or 8. That's why they have all those irritating announcements about which individual carriage number you are in, even when 8 of them were dropped off half an hour back...

 

[Hartington]

All very nice and all on trains around major connurbations. What's on the horizon for some of the rural routes where capacity is limited (at least in part) by platform length?

 

[SpacePhoenix]

Southern's SDO system (on the 377s) can select to individual carriage level, not just 4 or 8. That's why they have all those irritating announcements about which individual carriage number you are in, even when 8 of them were dropped off half an hour back...

Is that just down to the driver not selecting something on the TMS to inform it that x number of coaches have been uncoupled and the train is now only y coaches long?

Do any classes that don't have SDO installed have the internals already in place?

 

[najaB]

All very nice and all on trains around major connurbations. What's on the horizon for some of the rural routes where capacity is limited (at least in part) by platform length?

GPS works just as well in rural locations so if the desire is there, the technology is capable.

 

[cjmillsnun]

GPS works just as well in rural locations so if the desire is there, the technology is capable.

Gps's accuracy isn't that great without augmentation from known ground stations (having said that GSMR base stations could provide that information)

 

[najaB]

Gps's accuracy isn't that great without augmentation from known ground stations (having said that GSMR base stations could provide that information)

A-GPS can be accurate to a metre or less, certainly accurate enough for the train to know which station it is at.

 

[cjmillsnun]

A-GPS can be accurate to a metre or less, certainly accurate enough for the train to know which station it is at.

Yes differential GPS (i.e. augmented with fixed base station information) can be that accurate, but that kind of kit is normally surveyor grade kit usually used for mapping the position of buried utility infrastructure or by the OS for producing their premium mapping products for GIS systems. It is not cheap kit, and it is probably cheaper and easier to stick a balise on the track, or use a combination of consumer grade GPS (as used on PIS systems) and GSMR triangulation.

 

[TheJRB]

Southern's SDO system (on the 377s) can select to individual carriage level, not just 4 or 8. That's why they have all those irritating announcements about which individual carriage number you are in, even when 8 of them were dropped off half an hour back...

Southern's 171s also have SDO. I'm pretty sure Doleham and Three Oaks are can only accommodate one coach. I did see this sign at Normans Bay although I wonder how many times a four car 171 has called there!

Similarly Southeastern 375s also have SDO. If I remember rightly this is carriage level too (I think I remember leaving an 8-car 375 at Charing where only the front 6 opened).

 

[cjmillsnun]

Similarly Southeastern 375s also have SDO. If I remember rightly this is carriage level too (I think I remember leaving an 8-car 375 at Charing where only the front 6 opened).

Considering the very minimal differences between 375s and 377s (visibly only the DOO cameras) I would be very surprised if it wasn't carriage level.

 

[GatwickDepress]

Southern's 171s also have SDO. I'm pretty sure Doleham and Three Oaks are can only accommodate one coach. I did see this sign at Normans Bay although I wonder how many times a four car 171 has called there!

Similarly Southeastern 375s also have SDO. If I remember rightly this is carriage level too (I think I remember leaving an 8-car 375 at Charing where only the front 6 opened).

Yup, Doleham (40m) and Three Oaks (31m) can only accommodate one coach.


Doleham also has this 170 SDO sign, presumably used during testing, as it's nowhere near the 171 sign/s.


Doleham station: Class 170 door deselect sign by Sussex Eclectic, on Flickr

 

[swt_passenger]

All very nice and all on trains around major connurbations. What's on the horizon for some of the rural routes where capacity is limited (at least in part) by platform length?

I believe that the introduction of SDO to brand new routes requires fully automatic operation, controlled by the train's management system, the intention being to prevent train crew accidentally opening doors away from a platform.

What the above discussions have shown is that there are suitable auto SDO systems in use at the present time, which can control door release at individual door level, (in the 378s), not just at carriage level, so most of what you want in your first post can already be achieved.

ORR will probably determine on a case by case basis whether a new SDO method of operation will be allowed.

 

[tsr]

All very nice and all on trains around major connurbations. What's on the horizon for some of the rural routes where capacity is limited (at least in part) by platform length?

No problem at all on classes like the 171s, where the platform length is manually accommodated by the memory of the conductor and wherever they operate their local door from!

(On Class 171 DMUs, the conductor can either release their local door only, all doors, or all doors including their vehicle and those forward of it up to the driver's key - the latter being the door-deselect or SDO system).

 

[paul1609]

377s are already pretty clever a 4 car already opens the front 3 coaches at Pevensey Bay in the down direction and rear 3 in the up so not to block the crossing

 

[21C101]

If and when tube stock is built with walk through carriages like S stock,it might well be feasible to extend 6 car tube trains to 7 or 8 car using SDO, without extending the platforms, providing the terminus platforms and a handful of key locations are extended

Similarly you could extend Thameslink class 700 stock from 12 to 14 cars in the future the same way if you similarly extend Bedford and Brighton platforms, Blackfriars is also 14 car and St Pancras Low level looks extendable.

 

[trentside]

All very nice and all on trains around major connurbations. What's on the horizon for some of the rural routes where capacity is limited (at least in part) by platform length?

Well, the Class 222s are fitted with SDO. While their principal duties take them to and from London, it gives East Midlands Trains the facility to use them on local routes (e.g. Leicester to Lincoln and Derby to Crewe) which they do occasionally when required. Local guards based at Derby are apparently learning them to allow more regular strengthening of the Crewe services for the races at Uttoxeter or the football at Stoke (the drivers already know both traction and route).

With the 222s, there are buttons in the cab and the driver selects the appropriate SDO setting (indicated by a board at each station), which then allows the guard to release the doors from an appropriate position.