S7 Stock fitted with appropriate equipment for SMA

All S8 and all (except two) S7 trains were sent back to Derby for CBTC fitment.
All have now returned fully fitted.
This thread gave all of the details: www.districtdavesforum.co.uk/thread/15708/stock-delivery-introduction-discussion

It maybe that the S7 train you were on didn’t communicate correctly with the CBTC system at Edgware Road. The driver needs to check this while stationary in the platform and report if it doesn’t, then taking the alternate route towards High Street Kensington.

Whilst all trains are now fitted with the relevant signalling equipment, there are a large number of trains listed daily on the ‘non-VOBC’ (Vehicle On Board Computer, that is trains that can’t be used in the ATO area) - this could be for any number of reasons, but generally means there is a fault with the VOBC and the train would be ‘non-communicating’ with the signalling system.

In theory these trains should be confined to District Main services and not interface with the C&H, but occasionally they do get accidentally reformed, generally via Barking sidings, into C&H trains. The first that this is discovered is often at the ‘Check VOBC’ ‘entry’ (here meaning the last point before trains have to enter the ATO railway, rather than the specific CBTC meaning of entry) point in the platforms at Edgware Road.

Alternatively, for whatever reason, a VOBC may have gone defective on the previous journey, and for whatever reason the train cannot proceed. Although trains do have two VOBCs, it isn’t desirable to enter the area with one already defective. In this instance trains are generally reformed or diverted away from the area.

Of those options, the best is generally to perform a ‘stock and crew’ changeover with a District line service. All of these sets *should* be VOBC active, allowing trains to continue in service without cancellations. There may be a small amount of delay and disruption to those on the specific trains, but in the bigger picture this is the preferred option. A further stock and crew, usually at Earl’s Court, should then take place to put a fresh VOBC active train onto the Edgware Road Route, in case the issue happens again.

Alternatively, where the District train may not be itself VOBC active, the errant train would be diverted in order to keep services rolling. This is more disruptive, and happened a lot in the early days of the transition (particularly in cases where drivers were not yet fully familiarised on the ATO area). The preferred option is to push the train through to High Street Kensington and detrain, away to Triangle sidings and then bring it back out for its right time eastbound working at Edgware Road. If this too isn’t possible, the train would instead be diverted via the Inner Rail to Barking, running additionally around the south side of the Circle and then early against its own path east of Aldgate East. C&H drivers are trained on all three sides of the Aldgate triangle to permit workings such as this.

Let me get this straight:
At the moment, a train which shows up Non-VOBC at the start of an ATO area has to be diverted to a non-ATO route in order to proceed.
In future, this problem will be overcome by not having ANY non-ATO routes to divert to.
In which case, doesn't this mean that such a train will be 'failed in traffic'?
Nice solution. I love the flexibility built into these expensive upgrades.

The problem will indeed go away when ATO is universal, as no train in service can show up at the start of an ATO area if there are no non-ATO areas for it to come from.

Distilling the preceding comments, it seems that currently we have a thankfully rare transitional problem which currently only occurs at where ever the current SMA/non SMA boundary is, although presumably that potentially problematic location will change as further SMAs go live.

That does not seem ideal.

Presumably the best place to detect that a train has an issue is whilst it is still in the depot being prepared for service?

Let's fast forward to the point where the entire SSR system is operating under CBTC.

Yes the transitional problem has now gone, but we still have the issue of having nowhere to reroute any train which becomes defective whilst in service (except at snail pace) whenever both VOBC systems fail. The general policy of decanting the passengers the moment one or other VOBC shows a fault is understandable, but also not ideal.

Given the potential inconvenience for passengers let alone the impact on service levels, surely it makes sense to also enhance to system to minimise the incidence of failure in service.

Basically it cannot be beyond the system designers to design and install some sort of trackside monitoring system at the exit area of every depot, to automatically check that both VOBCs are working?

This would basically interrogate trains as they are heading into service and confirm that both VOBC systems are serviceable or automatically trigger the signalling system to route the train straight back to the depot for attention. The same system should ideally automatically alert the relevant depot staff of the fault(s) detected on the train to help minimise the time required to fix and return the train to service.

Sounds about right. The same could be assumed regarding the compressors. If one fails the train is taken out of service and sent to a depot.

If there is a fault prior to leaving the depot the train will not go into service in the same way any other fault would be handled..

My only concern is the lack of bolt holes on the increasing rationalised network but otherwise I can’t really see what the fuss is about?

Interesting......there are two per train S7/8?

I've spent four days trying to work it out (not full time, obviously), but I cannot come up with a viable meaning for 'SMA'.

Presumably the root of the S word is System, Service, or Signal, the M word is Management, and the A word is either Area or Automation, ... or am I way out?

That sounds very likely, except that the initial post refers to: 'SMA area'.

Of course, that could just be a case of 'Pin Number syndrome'. (Or: PINNS, {sometimes known as PINNS syndrome}.)

It is still up to date as of today just done my ATC(Automatic Train Control) refresher training and this map is what we were shown. Interestingly the reversing point at Aldgate East is to go but new reversing points both EB and WB are in place at Tower Hill for SMA03

I followed the link but couldn't find SMA listed. (Unless it is a reference to Small Heath station)

Thanks for your comments.
Hopefully I have now updated the list in the correct format
It probably would have been actioned after norbitonflyer comment without a further reminder.

My apologies, the night shifts are getting to me; I thought I'd added it to the list previously, and didn't double check that it was there. Thanks to DStock7080 for adding it for me, and not to worry about the double post - seems we're all in the habit of doing silly things at the moment!

Are non functioning VOBC's really going to be 'a thing?

Virtually every airbus in the sky relies on FBW {Fly By Wire} computer systems, to the extent that if one failed the aircraft would crash.

Obviously a failed VOBC is an acceptable risk on a train because it can simply do an emergency stop if necessary, but there's no reason to suppose it would be something that would happen more than once every few years. Assuming there has not been major incompetence in the design.

Does anyone know the level of redundancy in the controlling electronics in, say, S-Stock?