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Driverless Trains

The March 2017 Issue of E&T carries several articles about driverless cars but why haven't we got driverless mainline trains?

The technical 'problem' should be far simpler to solve than for a road vehicle. The position on the 'road' can be predicted and determined easily with precision. There is essentially no collision problem to solve, that has been done with the existing signalling system.

There is no need for communication with the train, no need for additional infrastructure. All that is needed is to observe and act on the existing fixed signals.

Of course such a basic system can be improved upon to produce a 'super driver' capable of reacting to unplanned obstructions, greasy rails etc.

The human driver is perhaps the last link to be made 'fail-safe' in the railway safety regime. Our efforts to 'improve' the driver-train interface have probably added new problems. Regular signal spacings, standard aspects and driver alerts must surely increase the boredom and inattention factor. An example of this was the Shap Roll-back in August 2010 where a driver correctly observed adverse signals, came to a stop, then allowed the train to roll-back, acknowledging the retreating adverse signals on the way, until the train exceeded 50 mph. Presumably he was half asleep?

I suspect the real 'problem' is a social one, it will be a tragedy if we can't solve that one.

0 Former Community Member over 7 years ago

I think the fundamental difference we need to consider is the automation of public transport vs. the automation of private transport.

Personally, I would resist a driverless car unless the law required it. Many people enjoy the ownership and the joy of driving a performance car, for example. There are others who don't really appreciate the machine that they are operating and only care that it gets them from A to B, and perhaps might be more open to driverless cars. This will ultimately be the driver (!) for investment and change.

With trains you don't really enjoy them. You might enjoy the view out of the window and being able to relax whilst traveling, but you don't get the enjoyment from actually operating the machine. In light of the recent tram accident (OK, not a train but it's public transport and there are some parallels) and the constant threat of industrial action, not to mention the state of Southern Trains, I can see how the public are more open to it, as long as it's safe.
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0 James Shaw over 7 years ago

David,

I think the main objections to driverless trains would come from the unions, the passengers aren't aware of the driver at all. I doubt if even little boys walk up to the head of the platform to see the engine and hopefully get to speak to the driver anymore. (A few months ago I was waiting in a delayed Paddington-bound express, a bit annoyed with myself that I had chosen it rather than the stopping train that should have followed it. Eventually we were told that they were waiting on a member of the train crew. Possibly the 'sandwich seller'? After a short pause we were given the additional bit of information that he was, err, the driver!).

I mostly enjoy driving my car but not in stop-go traffic and not on motorways, which are boring and scary when free-running 70 mph traffic abruptly changes to stop-go but how many drivers noticed? I would love to lock my car to the wire then.

The human perception of risk will also be a factor, we are a lot happier usually when we think we have control than when we give that control to others. Familiarity helps too. When the railways started some people didn't feel it would be safe to go faster than a horse and now 100 mph plus is commonplace. When one considers that the trains stay on the rails not by some sophisticated steering system but by the self-stabilising action of a pair of cones.. well I'd rather not consider it! (There is a subject for a "Why Engineer?" school talk here, all those little things that we rely on without a thought, the bolt that doesn't break, the screw that holds - built on centuries of knowledge and attention to detail).
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0 James Shaw over 7 years ago

Another thought following on from David's diversion via Driverless Cars, (Driverless Discussions wouldn't do that!), if the public accepted that they could have private space in a 'public' driverless vehicle, (i.e. they don't own a specific car), then that might get around the problem of the limited range of electric vehicles. A driverless electric car could call at your door and take you, say, 50 miles to a service area where you could refresh yourself and transfer to a new vehicle and so on to a distant destination.

I think I have just re-discovered the posting system of the horse transport days. Postillionless Carriages?
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0 Former Community Member over 7 years ago

Hi Andy, you quote 10^14 for track circuits. Do you have reference for that figure please. Just been in an argument with other people over removal of track circuits vs. unproven GPS location system. This would be helpful. Thanks. If you don't mind I will join the conversation below.

Andy Millar:

Hi James,

I would just add a couple of caveats to your thoughts.

Firstly, remember the level of safety you are trying to achieve. To satisfy the public acceptance of risk on the railways you need an unsafe equipment failure rate of (typically) one failure in 10^14 years. (As an example, this is what track circuits achieve.) This does not come cheaply - particularly in low volume equipment.

Secondly, unfortunately it is not going to be practical for any "line of sight" system (however automated) to brake a 200 tonne train travelling at 150mph on metal rails in its viewable distance - wheelspin detection is already in place, but to quote a famous engineer "ye canna change the laws of physics captain!" Hence the "block" system to keep trains a safe distance apart, and a huge amount of other activities to keep other obstructions off the line - which is why level crossings are such a problem.

I certainly agree that there need to be lessons shared between autonomous rail and autonomous road, however I suspect the learning process might go the other way to the one you expect. Road vehicles have traditionally been based on safety arguments based around driver intervention, with fully autonomous vehicles this argument changes completely. The rail industry has over 100 years experience of considering safety arguments based around automatic control methods, and there will be a lot of learning of how to approach a safety decision that will be transferrable. (Incidentally, ditto from aviation.) A key part of this - and I suspect, a particular area of upcoming controversy - is going to be transparency. Rail supply companies have to be fully transparent in their IP, no secrets are allowed about how their safety is assured. Once the risks of fully autonomous vehicles become fully apparent then the automotive industry, where extreme product secrecy is consider vital to staying ahead, could be in for a bit of a shock.

Interesting discussion, thank you. You might like to look at the UK "Digital Railway" project digitalrailway.co.uk to see what is coming along for the UK. Cash permitting there are some big changes ahead!

Andy
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0 Former Community Member over 7 years ago

Thanks for initiating this topic. It is timely and needed. I have just come off the Confederation Line Project in Ottawa and we have a UTO capable Light Rail vehicle ( it actually runs without a driver in the yard). But before you jump to conclusions, its primarily is a driver attended ATO vehicle with ATP. The costs of full UTO operation were not something the client wanted within their tight budget. Clearly the vehicle is fully capable in the future and I would hope the client will go that route but there is already huge resistance. My thought then turns to vehicle control systems: Perhaps to future proof the newer vehicles they should always be fitted with automatic systems and protection to allow the very real transition to what is undoubtedly the next step in rail evolution. If we are talking about autonomous vehicles, the best bang for the buck would be the gaining of experience of automatic operation on what already is a a very mature safe system and which can reliably demostrate protection of the public. Ironically Ottawa is mentioning the support of development of autonomous vehicles but has ignored what potential lies within their new rail vehicles. My other thought is that the freight industry should also not be complacent. there are a number of haulage companies in North america developing autonomous trucks, this should also be a wake up call to the rail freight industry and hopefully shake up their potential complacency. Imagine 24/7 trucks hauling goods.... hate to think at what that does to congestion.

That all said I am looking forward to seeing an autonomous streetcar/ Tram on the street very soon and why not? As to autonomous cars/automoblies , so far performance is great in a valley in San Bernadino or Paulo Alto. But put the cars on a Canadian road in the winter and factor in the calculation for worn tyres, communication delays and frictionless surfaces in your GEBR calculation, I am not sure the results will be all that good. Please don't even get me started on computing decisions and ethics of these systems.

Gareth
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0 Former Community Member over 7 years ago

James undoubtedly what you say has merit and is well founded. I distinctly remember a conversation in one of these forums ( maybe the older IEE) where Peter Sheppard was discussing the public's perception of safety with an Australian gentleman; whose name I unfortunately forget. It was a powerful discussion as to how safety is perceived by the Driver, passenger and ultimately the passenger without a train driver. In summary ...As the human is abstracted from control of their external environment the perception of that safe environment drammatically changes. Its an interesting idea and one that really stuck in my head.

The first London Underground automatic system although capable of being driverless still necessitated a driver thanks to the Unions ( Somebody can quote the line and year) so it probably didn't realise the benefits of a reduction in human staff. As another thought ,perhaps the name of driver has to now disappear as they are really only attendants or a reinvention of the guard.

James Shaw:

David,

I think the main objections to driverless trains would come from the unions, the passengers aren't aware of the driver at all. I doubt if even little boys walk up to the head of the platform to see the engine and hopefully get to speak to the driver anymore. (A few months ago I was waiting in a delayed Paddington-bound express, a bit annoyed with myself that I had chosen it rather than the stopping train that should have followed it. Eventually we were told that they were waiting on a member of the train crew. Possibly the 'sandwich seller'? After a short pause we were given the additional bit of information that he was, err, the driver!).

I mostly enjoy driving my car but not in stop-go traffic and not on motorways, which are boring and scary when free-running 70 mph traffic abruptly changes to stop-go but how many drivers noticed? I would love to lock my car to the wire then.

The human perception of risk will also be a factor, we are a lot happier usually when we think we have control than when we give that control to others. Familiarity helps too. When the railways started some people didn't feel it would be safe to go faster than a horse and now 100 mph plus is commonplace. When one considers that the trains stay on the rails not by some sophisticated steering system but by the self-stabilising action of a pair of cones.. well I'd rather not consider it! (There is a subject for a "Why Engineer?" school talk here, all those little things that we rely on without a thought, the bolt that doesn't break, the screw that holds - built on centuries of knowledge and attention to detail).
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0 Andy Millar over 7 years ago

Gareth Wood:

Hi Andy, you quote 10^14 for track circuits. Do you have reference for that figure please. Just been in an argument with other people over removal of track circuits vs. unproven GPS location system. This would be helpful. Thanks. If you don't mind I will join the conversation below.

Hi Gareth,

That was a bit naughty of me as I don't usually quote figures I can't publicly back up! If you look on my LinkedIn profile it won't take a lot of detective work to work out where that figure came from but as it isn't (afaik) published by Network Rail or Bombardier I'd better not go much further. And I may be an order of magnitude or two out (I wrote it from memory), but it's of around that order.

The bottom line is that I don't think there is any serious argument that a modern track circuit has any direct safety concerns whatsoever. There is a far more interesting discussion about the indirect risks due to reliability issues with track circuits, which then results in degredation to manual signalling which is phenomenally dangerous. Track circuit reliability can be vastly improved with condition monitoring, allowing pre-detection of failure conditions, but again it's a matter of expense. Maybe if a fatal accident occurs in degraded manual signalling mode which could have been prevented if (root cause) the track circuit had been readjusted / track connections repaired there will be more drive for this.

There was a very interesting IRSE presentation on Tuesday night by Network Rail & ProRail. This was explaining the possibility of a "hybrid" system running ETCS level 3 but with the existing block sections in place. Practically this could mean that the system could run level 3 (including autonomous!) trains interleaved with non-ETCS trains. It's just that there would be the existing large headway between the level 3 trains and unequipped trains. Very interesting for routes which mostly run fixed formation passenger stock with occasional freight trains. I'll be watching with interest.

Kind regards,

Andy
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0 Andy Millar over 7 years ago

James Shaw:

Andy,

I think the driverless train would do even better than a human driver at spotting obstructions to other traffic. I can't stress enough that this train will know its route better than any driver, photographically to the metre! It won't be looking the other way, it won't be speaking to train crew, it won't be drowsy.

While I can conceive of having a single driverless train, (it uses existing infrastructure), there is obviously scope to add more features with an expanded fleet. A 'down' train can report precisely to an approaching 'up' train any cautions - cow on line at 10,539 metres from York datum zero etc. and without the distraction that happens with a human driver - 'rubber necking'.

I fully appreciate and applaud the levels of safety that the rail industry in the UK has achieved but I think there is a safety gap that can be closed, 'the last link'? While I titled this topic 'Driverless Trains', knowing full well that for many that would be a leap too far, what stops such a system being trialled/developed as an 'add on'? Initially it needn't have any control input at all - 'mother-in-law' system! I bet there are universities out there that would love to run a 'camera in the cab' system project to see how well it would work and with absolutely no safety consequences.

Hi James,

Apologies for my slow reply - I got distracted into other less useful discussions on this forum! (Literally don't go there!)

The problem is the very high levels of safety and reliability you need. Even if you say this is an add-on that supplements rather than replaces the driver, so that the driver is the main control of the brakes and this has additional control, there are two huge problems. One is that it must not apply the brakes when it shouldn't - emergency braking a train is considered a hazard (there have been a number of serious passenger injuries caused by it). So it must never falsly think that something is on the track when it isn't. The other is more subtle, and was found in early adoptions of Automatic Train Protection. Once the driver knows there is an automatic protection system in place they will tend to rely on it, and if it isn't fail-safe horrible things can happen... These may be solveable, but are they solveable at a cost that is less than ETCS?

What may be interesting is a simple alarm system, so if a visual system picks up what it thinks is a hazard it alerts the driver who then decides what to do about it. That would have far fewer safety implications. But given the cost of railway approvals, due to the fact that no possible risk must come from any change, it would be 'interesting' getting it supported by major authorities. (Ref my comments above about this not influencing the accidents we're actually seeing.) If it were me, I'd start by looking at it as a tramway solution - which I'll bet someone already is!

You're probably aware that SPADs are a pure financial issue, the UK ATP system is in place for this, just needs to be rolled out more. (Or ETCS.) SPADs aren't quite as scary as the "red-tops" liked to make out in the early 2000s, there are huge protection zones in place. But they're not good of course - every time you degrade a safety margin then by definition there's a bit less left!

But regarding driverless trains generally, no problem, we've got them. And they meet the levels of safety demanded. If only we could afford them...

Rule one of railway engineering: Nothing is cheap, nothing is simple, unless you can persuade the public to compromise on safety,

Rule two of railway (and indeed safety) engineering: Every time you eliminate one Hazard, you create ten more!

It is very, very frustrating, being someone who is by instinct an innovation manager, to have to write posts like this. And as you can imagine, since I moved to the rail industry I've had many, many discussions like these. We desperately need innovations, particularly low cost innovations. But my (long!) experience has been that the only approach I've seen work is to start by working out how you're going to do it (whatever "it" is) safely and reliably at a "broad brush" level, and then work out the detailed technical solution - which is much the easier bit. Trying to start with a piece of whizzy technology and then trying to make it safe is a nightmare, indeed almost impossible. It's a strange business, and for some people quite a different approach to innovation - although personally I think you could apply it to any field.

So start with a problem, scope out several potential solutions, and then roughly work out what the risks in each of those are and how you are going to mitigate them - often you are truing to work out which is the "least worst". Taking SPADs: the problem is a signal not being seen, potential solutions include driver training, driver shift reduction, change of design of the signal, in cab signalling, radio link from the signal to the train, track induction link from the track to the train, double signals (the old home and distant), vision system (that's just what I came up with while writing that sentence, I'm not pretending it's an exhaustive list). Then for each of those there are a range of risks (safety and reliability), costs and benefits, and what you'll probably come up with is a solution that looks pretty much like ATP funnily enough! Also remember that the simpler and lower tech a solution is a) the more reliable it is likely to be and b) the easier it is to prove it's safe (because it has less failure modes).

So if you're promoting an innovation for a safety critical environment, somehow you need to get it in the minds of the right people when they are going through that selection of options stage, which is a HUGE challenge for the industry. But you must have an argument ready for every immediately apparent safety and reliability issue - which for vision systems unfortunately are many and varied.

For anyone interested in understanding this process further, a good starting point is RSSB's "Taking Safe Decisions" www.rssb.co.uk/.../2014-guidance-taking-safe-decisions.pdf

Don't know if I've explained that very well, very happy to discuss and clarify further! Once you move away form a particular case and get into the more general case it becomes very interesting - and quite important - which I suppose is why several universities are now running master's degrees in this stuff!

Cheers,

Andy
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0 Andy Millar over 7 years ago

P.S. Apologies for typos - I was being reminded that I was supposed to be putting dinner in the oven, not typing away om my laptop!
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0 Andy Millar over 7 years ago

Ahhh...when I looked properly I was somewhat ambitious regarding complete track circuit safety (Wrong Side Failure) rates, think in the order of 10^-9 failures per hour and you won't be far off...
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Driverless Trains

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