0:00:03 > 0:00:07Every morning, hundreds of thousands of passengers
0:00:07 > 0:00:09all over the country rely on trains to get to work.
0:00:09 > 0:00:14And that number is growing rapidly every year.
0:00:14 > 0:00:17As we all know, our trains are great when they work,
0:00:17 > 0:00:20but they are a nightmare when they go wrong.
0:00:22 > 0:00:24Tonight on Bang,
0:00:24 > 0:00:26we scrutinize our rail system and ask
0:00:26 > 0:00:31how is it ever going to deal with the surge in passenger numbers?
0:00:33 > 0:00:38We see how we can squeeze more trains on to the existing tracks...
0:00:38 > 0:00:41All of this technology is going to revolutionize the way
0:00:41 > 0:00:45our railways will be run in the future.
0:00:45 > 0:00:48..how the weakest link is often the rails themselves...
0:00:48 > 0:00:52When a tiny crack from a bolt hole deepens,
0:00:52 > 0:00:56the consequences are not good.
0:00:56 > 0:01:01And the truth behind frustrating delays caused by the "wrong kind of leaf"....
0:01:01 > 0:01:04Wow. That is pretty incredible.
0:01:10 > 0:01:1530 years ago, Britain's rail system was seen as a bit of a disaster.
0:01:15 > 0:01:18But they've truly turned the corner.
0:01:18 > 0:01:231.5 billion people a year use 7.2 million train services
0:01:23 > 0:01:27over 32,000 kilometres of track.
0:01:27 > 0:01:32And passenger numbers are predicted to double in the next 30 years.
0:01:32 > 0:01:36But even with new lines like Crossrail
0:01:36 > 0:01:40and possibly HS2 due to come on stream, the real problem is how to
0:01:40 > 0:01:43increase the capacity on the tracks we already have.
0:01:44 > 0:01:48And one way to do that could be to change the way the signals work.
0:01:51 > 0:01:54Signals are not only used to keep the trains apart -
0:01:54 > 0:01:58they maximise capacity by keeping them as close together as is safe.
0:01:58 > 0:02:00For over 100 years,
0:02:00 > 0:02:04the safest and most reliable way of controlling and managing the railways
0:02:04 > 0:02:07has been the Fixed Block system.
0:02:07 > 0:02:09It's actually pretty straightforward.
0:02:09 > 0:02:14First divide your track up into blocks potentially a few
0:02:14 > 0:02:17kilometres long, separated by a signal.
0:02:17 > 0:02:18This is the safety zone.
0:02:21 > 0:02:23Then use the signals to let a train know
0:02:23 > 0:02:25if it can safely enter a block or not.
0:02:25 > 0:02:27And the simple rule is this.
0:02:27 > 0:02:29If you have got a train in this block,
0:02:29 > 0:02:33the next train is forbidden from entering it until the train
0:02:33 > 0:02:36exits the block.
0:02:36 > 0:02:39So this signal will stop this train from coming into
0:02:39 > 0:02:42the block until this signal here has registered that this train has left.
0:02:43 > 0:02:46As long as this rule is followed,
0:02:46 > 0:02:48a collision is simply not possible.
0:02:50 > 0:02:53The Fixed Block signalling system is safe and successful.
0:02:55 > 0:02:57But it's also somewhat inefficient
0:02:57 > 0:03:00because to remain safe, all these blocks
0:03:00 > 0:03:04need to be pretty big so the tracks end up mainly empty.
0:03:04 > 0:03:08With our ever-increasing demand for trains,
0:03:08 > 0:03:12can the system that governs how our railways operate be improved, safely?
0:03:15 > 0:03:17Well, perhaps we can learn something
0:03:17 > 0:03:19from how vehicles flow on our roads.
0:03:24 > 0:03:27I'm driving at 50 miles an hour
0:03:27 > 0:03:29and if I need to make an emergency stop,
0:03:29 > 0:03:33the Highway Code dictates that I would need a total distance of 53 metres -
0:03:33 > 0:03:35that's 38m of braking distance
0:03:35 > 0:03:37and 15m of thinking distance.
0:03:39 > 0:03:41And if traffic builds up and I slow down,
0:03:41 > 0:03:44my stopping distance, obviously, falls.
0:03:44 > 0:03:46The faster I am going,
0:03:46 > 0:03:49the larger the space in front needs to be.
0:03:49 > 0:03:52And if I slow down, that space gets smaller.
0:03:53 > 0:03:56We could increase capacity on the railways
0:03:56 > 0:03:58by getting trains to follow these principles too.
0:03:59 > 0:04:03It's essentially like turning a fixed block system
0:04:03 > 0:04:05into a moving block.
0:04:05 > 0:04:07And that's going to make all the difference.
0:04:07 > 0:04:09So how would you make it work?
0:04:09 > 0:04:12Well, you'd need to know everything about the train in front -
0:04:12 > 0:04:15how fast it was moving, and its position.
0:04:16 > 0:04:19And if you knew your speed and your position,
0:04:19 > 0:04:23you could then calculate how close you can travel behind the first train safely.
0:04:23 > 0:04:24Simple. In theory.
0:04:28 > 0:04:30And it's exactly what they do here,
0:04:30 > 0:04:33at the Docklands Light Railway in East London.
0:04:33 > 0:04:36Each train's exact position is worked out
0:04:36 > 0:04:38using wires laid out along the track.
0:04:42 > 0:04:44These wires transmit signals to and from the trains.
0:04:46 > 0:04:52The loops of cable cross over every 25 metres along the track,
0:04:52 > 0:04:54and here's one of those points.
0:04:54 > 0:04:58Now, the train counts the amount of times that it travels over
0:04:58 > 0:05:01one of these cross points and that's the crucial part of the system.
0:05:03 > 0:05:06The train can count these cross points
0:05:06 > 0:05:09because the electrical signal changes direction at each twist.
0:05:12 > 0:05:15This is the train's on-board computer system,
0:05:15 > 0:05:17the nerve centre of the train,
0:05:17 > 0:05:20and let me show you what happens when the train passes over
0:05:20 > 0:05:22one of these crossover points.
0:05:22 > 0:05:25The current is running in one direction as the train
0:05:25 > 0:05:27approaches the crossover.
0:05:27 > 0:05:31At the crossover, it flips 180 degrees, what's called a phase change.
0:05:31 > 0:05:35This oscilloscope measures the direction of the signal below
0:05:35 > 0:05:40and you can see how it flips as the loop passes underneath the train.
0:05:42 > 0:05:45And it's this that the train registers
0:05:45 > 0:05:48and counts every time it passes over a crossover.
0:05:50 > 0:05:54Each pulse identifies the train's position within the 25-metre loop.
0:05:57 > 0:05:59Then a second system measures
0:05:59 > 0:06:01how many times each train wheel rotates.
0:06:04 > 0:06:07Between these two systems, the train position can be tracked
0:06:07 > 0:06:09down to just a few centimetres.
0:06:11 > 0:06:15The exact speed and position of each train is relayed back to this
0:06:15 > 0:06:19control centre and the computer system here calculates how
0:06:19 > 0:06:22close to each other the trains can travel safely.
0:06:22 > 0:06:25That information is then relayed back to the trains
0:06:25 > 0:06:27so they can move accordingly.
0:06:29 > 0:06:33Using moving block, the DLR's system is able to run more trains,
0:06:33 > 0:06:37closer together, than a conventional fixed block system.
0:06:37 > 0:06:40Which means the line capacity can be far greater.
0:06:42 > 0:06:45And it's flexible enough to be able to deal with almost any
0:06:45 > 0:06:47unexpected occurrence with ease.
0:06:48 > 0:06:51The police just delayed the train at platform two.
0:06:51 > 0:06:54Any idea why that was?
0:06:54 > 0:06:57And the system is so safe, it's not only done away with all signals,
0:06:57 > 0:07:00but there's also the need for on-board drivers.
0:07:01 > 0:07:04Thanks to all this technology, moving block is going to
0:07:04 > 0:07:07revolutionize the way our railways will be run in the future,
0:07:07 > 0:07:11dramatically increasing rail capacity and efficiency.
0:07:13 > 0:07:16With the technology now tried and tested,
0:07:16 > 0:07:19the moving block system is being considered for roll out over
0:07:19 > 0:07:21the entire national rail network.
0:07:23 > 0:07:25And with this change,
0:07:25 > 0:07:28we could begin to see more trains and hopefully less overcrowding.
0:07:33 > 0:07:37But more and faster trains on the tracks has a serious downside.
0:07:37 > 0:07:40The rails themselves wear out a lot quicker.
0:07:40 > 0:07:43And this can add up to more inefficiencies, as the tracks
0:07:43 > 0:07:46are manually checked and mended.
0:07:51 > 0:07:57This may not look special, but that train behind me is the fastest engineering train in the UK
0:07:57 > 0:07:59and it's packed with technology.
0:08:01 > 0:08:05On board is the revolutionary rail measurement system called
0:08:05 > 0:08:08Plain Line Pattern Recognition,
0:08:08 > 0:08:12most of which is carried just centimetres from the track.
0:08:12 > 0:08:15Underneath the train you've got an array of monitoring equipment.
0:08:15 > 0:08:18Underneath here you've got two lasers which are capturing
0:08:18 > 0:08:23the track geometry and then here you've got seven cameras monitoring
0:08:23 > 0:08:28the track from sleeper end to sleeper end in incredible detail.
0:08:30 > 0:08:32This level of scrutiny is required
0:08:32 > 0:08:37because of the unbelievable stresses the rails themselves are under.
0:08:37 > 0:08:42When the train is moving, the wheels touch a tiny surface area
0:08:42 > 0:08:46of the track and in fact, if you were to take the entire length of the train,
0:08:46 > 0:08:50the total area covered is less than two mobile phones put together.
0:08:50 > 0:08:53So you can imagine, with 100 tonnes
0:08:53 > 0:08:59of train pressing down on that tiny surface area, it's got to take its toll.
0:09:03 > 0:09:07Most significant is a phenomenon called rolling contact fatigue,
0:09:07 > 0:09:11which is a result of stressing the rail as the wheel
0:09:11 > 0:09:13presses down over and over again.
0:09:15 > 0:09:18In fact, over its lifetime, a single rail will end up
0:09:18 > 0:09:21stressed by over a billion tonnes' worth of trains.
0:09:24 > 0:09:27And the impact is worse at bends, where
0:09:27 > 0:09:30the full weight of the train is thrown at the outer rail.
0:09:33 > 0:09:35This is an example of rail fatigue.
0:09:35 > 0:09:39If you look, those tiny cracks may look really innocent.
0:09:39 > 0:09:43But over time, they are going to deepen and spread.
0:09:43 > 0:09:46And eventually, they can become very dangerous.
0:09:46 > 0:09:50The consequences are similar to what happens
0:09:50 > 0:09:55if I start bending a hacksaw blade, in that initially with that pressure
0:09:55 > 0:10:00you are OK, but with continued pressure, that's what happens.
0:10:00 > 0:10:05The cracks deepen, the rail splits apart and you are in deep trouble.
0:10:10 > 0:10:13Good evening. Four people have been killed and dozens injured
0:10:13 > 0:10:17after an Intercity train derailed at high speed in Hertfordshire.
0:10:18 > 0:10:23On the 17th of October 2000, an Intercity 225 bound for Leeds
0:10:23 > 0:10:28entered a bend just south of Hatfield at around 185kph.
0:10:28 > 0:10:33As the forces mounted, the outer rail failed and the whole train
0:10:33 > 0:10:38derailed. Four people lost their lives and over 70 were injured.
0:10:39 > 0:10:42And rails can fail in other ways too.
0:10:43 > 0:10:46This piece of rail had a manufacturing defect
0:10:46 > 0:10:48and with pressure, it grew
0:10:48 > 0:10:51and you can see that is not looking healthy at all.
0:10:51 > 0:10:58And then here, this is what happens when a tiny crack from a bolt hole deepens
0:10:58 > 0:11:01and as you can see, the consequences are not good.
0:11:01 > 0:11:05Rails can be vulnerable in a number of other different ways.
0:11:05 > 0:11:08Their fasteners can come adrift, the joints can be misaligned,
0:11:08 > 0:11:11and the clamps go missing.
0:11:11 > 0:11:14Any one of those can cause a disaster.
0:11:16 > 0:11:19Rail maintenance is a huge commitment for Network Rail,
0:11:19 > 0:11:21costing millions of pounds a year
0:11:21 > 0:11:25and it's one they obviously take very seriously.
0:11:26 > 0:11:30Up until now, most of the inspection work on the railway
0:11:30 > 0:11:33has been done by men walking along the track,
0:11:33 > 0:11:35spending millions of hours
0:11:35 > 0:11:38checking and rechecking the state of the rails.
0:11:38 > 0:11:41But that is far from ideal.
0:11:41 > 0:11:46- The problem with manual inspection is that it is very slow- -
0:11:46 > 0:11:50each rail has to be scrupulously surveyed by experts every few weeks.
0:11:50 > 0:11:55Inspectors on the tracks is always a safety issue and of course, all this
0:11:55 > 0:11:59time required for inspection ends up having an impact on passengers too.
0:12:00 > 0:12:04But the new measurement train should make a real difference.
0:12:04 > 0:12:08We're travelling at 100mph and if you take look at that
0:12:08 > 0:12:11screen there, you can see the live images coming from the cameras
0:12:11 > 0:12:13underneath the train.
0:12:13 > 0:12:17All of the data is being collated and stored here and then
0:12:17 > 0:12:21when we get back to base, the drive can be removed and analysed.
0:12:23 > 0:12:28The software then interprets the images and identifies potential problems.
0:12:28 > 0:12:32Those problems can be then checked by inspection experts, who can
0:12:32 > 0:12:34order the appropriate action.
0:12:34 > 0:12:38It could be the start of a crack appearing in a joint or a weld
0:12:38 > 0:12:41and if it goes unnoticed,
0:12:41 > 0:12:44that weak point will carry on getting damaged.
0:12:44 > 0:12:48We try to find it early before a problem occurs.
0:12:48 > 0:12:51Do you know, the quality is just astounding,
0:12:51 > 0:12:54bearing in mind that the train can be travelling at over 100mph.
0:12:54 > 0:12:57Finding cracks and things like that is very easy
0:12:57 > 0:13:00because you can zoom in so for and the quality is perfect.
0:13:02 > 0:13:06When a fault is found, their position is marked by GPS and
0:13:06 > 0:13:10repair teams are sent direct to the problem within days or even hours.
0:13:10 > 0:13:14At the moment, the new measurement train is covering
0:13:14 > 0:13:16over 100,000 miles a year,
0:13:16 > 0:13:18and potentially, it can be
0:13:18 > 0:13:22rolled out across the whole of our railway network,
0:13:22 > 0:13:25significantly reducing trackside inspections
0:13:25 > 0:13:28and ultimately increasing rail capacity.
0:13:28 > 0:13:31Matt Brassington is the project manager.
0:13:31 > 0:13:34Can this technology really replace the experienced
0:13:34 > 0:13:36eye of the track inspector?
0:13:36 > 0:13:38The inspectors on the train
0:13:38 > 0:13:41are actually qualified track inspectors themselves
0:13:41 > 0:13:43and the software that we have
0:13:43 > 0:13:46replicates what they would do on the ballast.
0:13:46 > 0:13:50The system in its totality is far, far better than you would
0:13:50 > 0:13:53get from a track patroller.
0:13:53 > 0:13:55How many hours will this save you?
0:13:55 > 0:13:58Originally it took up to about 1.5 million man hours
0:13:58 > 0:14:00to inspect national Network Rail's infrastructure.
0:14:00 > 0:14:05This has now been halved by the introduction of plain line pattern recognition.
0:14:05 > 0:14:09And this has a direct impact on passengers.
0:14:09 > 0:14:12Fewer hours wasted by maintenance patrols on the tracks
0:14:12 > 0:14:16means routes are not out of action and can carry more passenger trains.
0:14:16 > 0:14:19So that's more convenient for passengers
0:14:19 > 0:14:21and much safer for the inspection crews.
0:14:25 > 0:14:30The New Measurement Train is an impressive piece of technology
0:14:30 > 0:14:33which should put an end to some of those frustrating
0:14:33 > 0:14:38delays on the line and also prevent faults from becoming tragedies.
0:14:38 > 0:14:42But there is one problem that not even this train can sort out
0:14:42 > 0:14:46and that's the age-old issue of leaves on the line.
0:14:49 > 0:14:52It sounds like the worst excuse imaginable.
0:14:52 > 0:14:54How could something as insignificant as leaves
0:14:54 > 0:14:56affect a 100-tonne train?
0:14:56 > 0:14:59But they do.
0:14:59 > 0:15:04In 2002, leaves caused over 500 days' worth of delays.
0:15:04 > 0:15:06And it's ultimately
0:15:06 > 0:15:10because of how the train's wheels roll on the rails themselves.
0:15:12 > 0:15:15One of the reasons that trains are so efficient at pulling heavy loads
0:15:15 > 0:15:20whilst expending very little energy is the fact that their steel wheels,
0:15:20 > 0:15:22running on a steel rail,
0:15:22 > 0:15:25produce very little of what's called 'rolling resistance'.
0:15:29 > 0:15:31When any wheel rolls across a surface,
0:15:31 > 0:15:35the mass pressing down in it will cause it to deform.
0:15:37 > 0:15:41The larger that deformation, like in the case of a semi-flat tyre,
0:15:41 > 0:15:43the greater the rolling resistance.
0:15:44 > 0:15:48As the wheel deforms, energy is lost
0:15:48 > 0:15:51and I can tell you, it makes it much harder to cycle a bike.
0:15:54 > 0:15:57On a train, the deformation in the hard steel wheels
0:15:57 > 0:15:59and on the rail is incredibly minor,
0:15:59 > 0:16:02which equates to a tiny amount of rolling resistance.
0:16:03 > 0:16:06But when it comes to stopping and starting,
0:16:06 > 0:16:09steel on steel presents some real problems.
0:16:10 > 0:16:14Let me show you what I mean using these two steel weights
0:16:14 > 0:16:15and this steel plate.
0:16:15 > 0:16:17The only difference between these two bits of steel
0:16:17 > 0:16:21is that there is a bit of rubber on the underside of this one.
0:16:21 > 0:16:23Watch what happens when I tip the plate.
0:16:25 > 0:16:27Of course the one without the rubber beneath it
0:16:27 > 0:16:29slips to the bottom quickly.
0:16:32 > 0:16:35Luckily, under normal conditions, there is just enough
0:16:35 > 0:16:39grip between the wheels and the track to allow the trains to
0:16:39 > 0:16:40start with ease and, more importantly,
0:16:40 > 0:16:42to stop safely.
0:16:46 > 0:16:49But when there are leaves on the line it's a different matter.
0:16:49 > 0:16:52You see, leaves are made up of about 80% water,
0:16:52 > 0:16:54and the rest is a complex combination
0:16:54 > 0:16:57of other substances, including cellulose, pectin
0:16:57 > 0:16:59and a type of fatty acid which
0:16:59 > 0:17:01happen to have lubricating properties.
0:17:03 > 0:17:06Research has shown that soggy, slippy leaves are actually
0:17:06 > 0:17:09sucked onto the track by the passing trains.
0:17:10 > 0:17:14And once on the track, they are crushed to a pulp by the wheels.
0:17:16 > 0:17:20The result is a thin black layer of crushed leaf matter,
0:17:20 > 0:17:22about 25 microns thick -
0:17:22 > 0:17:25that's thinner than the width of a human hair.
0:17:25 > 0:17:27And when you get a little bit of rain,
0:17:27 > 0:17:29this layer becomes incredibly slippery.
0:17:31 > 0:17:35This means that at peak time in the autumn, to avoid slipping,
0:17:35 > 0:17:38trains have to accelerate and decelerate
0:17:38 > 0:17:43much more slowly than normal, resulting in frustrating delays.
0:17:43 > 0:17:48So what does leaves on the line mean in terms of stopping distances?
0:17:48 > 0:17:53When Nick and Ian slammed on the brakes at the stop flag over there,
0:17:53 > 0:17:55this is where they came to a stop,
0:17:55 > 0:17:58and it's roughly where they would end up under normal conditions.
0:17:58 > 0:18:02But what would happen if there were crushed leaves on the rails?
0:18:03 > 0:18:05We'll simulate the slippery effect of leaves by using
0:18:05 > 0:18:08a mix of washing up liquid and water.
0:18:08 > 0:18:12This stuff is actually less slippery than crushed wet leaves,
0:18:12 > 0:18:15but it's easier to apply, which is why rail companies use this
0:18:15 > 0:18:19when they are training drivers to handle low-adhesion conditions.
0:18:21 > 0:18:25Right, let's see what happens now when the train tries to stop.
0:18:25 > 0:18:26All right, lads.
0:18:35 > 0:18:38Here were go - they are about to slam on the brakes at the stop flag.
0:18:42 > 0:18:44Whoa...
0:18:44 > 0:18:45Wow.
0:18:50 > 0:18:53That it pretty incredible -
0:18:53 > 0:18:56three times the distance it stopped originally.
0:18:56 > 0:19:00Our test is limited to a train speed of 16 kilometres per hour,
0:19:00 > 0:19:03and we only prepared 18 metres of line.
0:19:03 > 0:19:06Imagine what the effect would be on a 200-tonne express
0:19:06 > 0:19:09travelling at 160 kmph.
0:19:11 > 0:19:13And this is ultimately why leaves on the track
0:19:13 > 0:19:15is no joke.
0:19:15 > 0:19:17And you might think to yourself, "Why not just
0:19:17 > 0:19:19"cut the trees bordering the railway line?"
0:19:19 > 0:19:21But it's not as simple as that.
0:19:23 > 0:19:27The answer goes back over 50 years...
0:19:27 > 0:19:29Back in the steam locomotive era,
0:19:29 > 0:19:33line-side vegetation was kept down by fires caused by sparks
0:19:33 > 0:19:35from the trains engines.
0:19:35 > 0:19:38But as new diesel and electric trains took over from steam,
0:19:38 > 0:19:39the trees thrived.
0:19:42 > 0:19:44Now the trees are mature.
0:19:44 > 0:19:46Of course, conservation plays a part here,
0:19:46 > 0:19:48but even if ecologists agreed,
0:19:48 > 0:19:53it would cost £2.5 billion to remove the trees along our tracks,
0:19:53 > 0:19:55making it financially unrealistic.
0:19:55 > 0:19:59Instead, Network Rail can use high-speed water jets
0:19:59 > 0:20:01which blast the leaves off the track,
0:20:01 > 0:20:04and lay a mix of sand and aluminium, to aid traction.
0:20:06 > 0:20:09But it's not only leaves on the line that cause delays.
0:20:09 > 0:20:12There is something else that should never be only the line.
0:20:12 > 0:20:13And that's us.
0:20:15 > 0:20:19To give you an example, last year, not a single person was killed
0:20:19 > 0:20:20whilst on a train,
0:20:20 > 0:20:23but 20 people lost their lives by being accidently
0:20:23 > 0:20:27hit by a train - and they were all trespassing on the railway lines.
0:20:29 > 0:20:31As well as the loss of human life,
0:20:31 > 0:20:35the effect on the network of such a tragedy is massive.
0:20:36 > 0:20:41In January 2013, the cumulative delays caused by reports of
0:20:41 > 0:20:44trespasses and collisions was a staggering 45 days.
0:20:45 > 0:20:48When you analyse the data, the victims were trying to
0:20:48 > 0:20:50retrieve a lost phone or wallet, they were taking a short cut,
0:20:50 > 0:20:54and the vast majority were young males aged between 16 and 30
0:20:54 > 0:20:57coming home after a late night on the weekend.
0:20:57 > 0:21:01Now, bravado and alcohol play a role in those fatalities,
0:21:01 > 0:21:04but for all the victims, there might be another factor at play
0:21:04 > 0:21:07that you might find surprising - hearing.
0:21:07 > 0:21:11If I was standing on a track, I would be able to hear a train
0:21:11 > 0:21:13coming towards me, definitely.
0:21:13 > 0:21:18It's echoey and loud. You're going to hear it. It's going fast.
0:21:18 > 0:21:21I'd imagine I would hear a train...
0:21:21 > 0:21:22Probably.
0:21:22 > 0:21:24They tend to make a bit of noise,
0:21:24 > 0:21:27and occasionally they sound a horn, don't they?
0:21:32 > 0:21:35More than a third of us are convinced we'd be able
0:21:35 > 0:21:38to hear a train coming soon enough to get out of the way.
0:21:42 > 0:21:43But could we?
0:21:46 > 0:21:49Scientists at the University of Salford are finding out how
0:21:49 > 0:21:54fast people can react to a speeding train using an anechoic chamber.
0:21:58 > 0:22:01So this is what an anechoic chamber looks like.
0:22:01 > 0:22:03Nice to meet you.
0:22:03 > 0:22:05So what are we going to do in here?
0:22:05 > 0:22:08So we are testing people's ability to detect an oncoming train
0:22:08 > 0:22:11when they are standing by a rail track.
0:22:11 > 0:22:14- So I'm going to be your guinea pig. - Yes.- What do you need me to do?
0:22:14 > 0:22:16I need you to sit on that chair over there.
0:22:16 > 0:22:18All right.
0:22:18 > 0:22:21In this completely silent space,
0:22:21 > 0:22:24Dr Fazenda will recreate the sound a train makes as it passes.
0:22:26 > 0:22:27The moment I hear it,
0:22:27 > 0:22:30I have to press the keyboard to stop the train and then
0:22:30 > 0:22:33identify its direction and speed...
0:22:33 > 0:22:36- All right, Bruno, let's go for it.- OK.
0:22:38 > 0:22:40TRAIN APPROACHING
0:22:40 > 0:22:44I think something was coming from the right.
0:22:44 > 0:22:46TRAIN APPROACHING
0:22:46 > 0:22:49- Slow.- OK.
0:22:51 > 0:22:54- TRAIN ON RAILS - Left.
0:22:54 > 0:22:56That was a fast train.
0:22:57 > 0:22:58OK, so how did I do?
0:22:58 > 0:23:00You missed one out of three
0:23:00 > 0:23:05and unfortunately, one miss is one death.
0:23:05 > 0:23:07- So I would be dead? - Yes, on one occasion.
0:23:07 > 0:23:10It's far more difficult that I would have imagined.
0:23:12 > 0:23:15Even with no distractions, I still got one wrong.
0:23:17 > 0:23:20How much harder would it be in the outside world?
0:23:24 > 0:23:27What would happen if your hearing was impaired or muffled
0:23:27 > 0:23:29because you were listening to music on headphones,
0:23:29 > 0:23:32or had just been at a loud concert or bar?
0:23:33 > 0:23:36The reason why sound can become muffled after being exposed
0:23:36 > 0:23:38to loud music in a nightclub is
0:23:38 > 0:23:41actually due to a protective mechanism within the ear.
0:23:41 > 0:23:46Your ear is made up of the outer, middle and inner ear.
0:23:46 > 0:23:50And the eardrum is connected to the inner ear by three little
0:23:50 > 0:23:55bones that lever to allow the sounds to reach the inner ear.
0:23:55 > 0:23:56Now when you are exposed to loud music,
0:23:56 > 0:24:00the brain registers this loudness and signals to the muscles
0:24:00 > 0:24:03attached to these little bones to tense up.
0:24:03 > 0:24:05And so, the bones don't lever quite so much,
0:24:05 > 0:24:08and minimise the amount of sound which reaches the inner ear.
0:24:08 > 0:24:12- LOUD MUSIC AND MUFFLED SPEECH - Now this is reversible - it's temporary hearing loss...
0:24:12 > 0:24:16Now this is reversible - it's temporary hearing loss,
0:24:16 > 0:24:18but it can last several hours depending on the length
0:24:18 > 0:24:21of exposure and the loudness of the sound you have been exposed to.
0:24:26 > 0:24:30Because we can't get our subject exposed to loud sound,
0:24:30 > 0:24:36we filter the signals to emulate how we would hear the sound as
0:24:36 > 0:24:37if they had been in a nightclub.
0:24:37 > 0:24:39So it's going to be more muffled?
0:24:39 > 0:24:41Yes.
0:24:41 > 0:24:44But muffled hearing isn't the only factor at play here.
0:24:44 > 0:24:47Another hazard is concentration.
0:24:47 > 0:24:50In the first test, the train had my full attention.
0:24:50 > 0:24:53But the reality is that much of the time we aren't
0:24:53 > 0:24:56giving our surroundings our full attention because we are
0:24:56 > 0:25:00listening to music, talking with friends or using our phones.
0:25:02 > 0:25:04And I'm thinking, who would realistically
0:25:04 > 0:25:06look at their phone when we are crossing the track?
0:25:06 > 0:25:08But we are so used to hearing, "Beep-beep",
0:25:08 > 0:25:12you are quite likely to whip it out and see who's been contacting you,
0:25:12 > 0:25:13as you're doing something.
0:25:15 > 0:25:19As I listen to the muffled sound, Dr Fazenda simulates this lack of
0:25:19 > 0:25:22attention by having me read a book.
0:25:22 > 0:25:24The book will give us the situation
0:25:24 > 0:25:27where your attention is diverted into reading the book.
0:25:27 > 0:25:30So you'll have to read a passage of this book out loud.
0:25:30 > 0:25:31Out loud?!
0:25:31 > 0:25:35Yes, so I know that you are actually paying attention,
0:25:35 > 0:25:40and the task is still to tell me where the train is coming from.
0:25:40 > 0:25:43I shall read the chapter on cake and carpentry.
0:25:43 > 0:25:45That sounds very good.
0:25:45 > 0:25:51"Whitstable is wonderful, the sort of place where Enid..."
0:25:51 > 0:25:52Right.
0:25:52 > 0:25:54Slowish, I think...
0:25:54 > 0:25:58"The sort of place where Enid Blyton children still go to buy ginger pop
0:25:58 > 0:26:00"and paper kites for a shilling..."
0:26:00 > 0:26:04Whoa! That was a bit close.
0:26:04 > 0:26:05Am I dead!?
0:26:05 > 0:26:07"With shopping bags, off to buy
0:26:07 > 0:26:10"a bit of haddock for his lordship's tea."
0:26:10 > 0:26:13That was right and it was really fast.
0:26:13 > 0:26:17- OK.- How many times did I die on the tracks?
0:26:17 > 0:26:19I'm afraid you have died twice.
0:26:21 > 0:26:23Why? What did I get wrong?
0:26:23 > 0:26:26Both of these trains sneaked up on you before you were able
0:26:26 > 0:26:28to tell they were there.
0:26:28 > 0:26:30And what is more interesting is that
0:26:30 > 0:26:34- you are getting your sides wrong a lot more and the speeds.- Really?!
0:26:34 > 0:26:37So why did I get the direction wrong?
0:26:37 > 0:26:40One of the things is because your hearing system
0:26:40 > 0:26:43has been somewhat changed you are
0:26:43 > 0:26:47missing out some of the frequency content which will give you a better
0:26:47 > 0:26:51estimation of direction and that, of course, is one of the problems.
0:26:51 > 0:26:54The other problem is that your attention is somewhere else,
0:26:54 > 0:26:57so to estimate something that is a little bit more critical,
0:26:57 > 0:27:01requires a bit more thought and you haven't got that cognitive
0:27:01 > 0:27:04ability any more because you are focusing on something else.
0:27:04 > 0:27:09It is shocking how dangerous this actually is from being distracted
0:27:09 > 0:27:12a little bit from having been out in a loud place.
0:27:12 > 0:27:14It's sobering.
0:27:17 > 0:27:20Dr Fazenda has repeated this experiment with many
0:27:20 > 0:27:23different subjects, and the results are always the same.
0:27:31 > 0:27:34It all adds up - the way sound emanates from trains,
0:27:34 > 0:27:36listening to loud music, distractions,
0:27:36 > 0:27:38they are all a recipe for disaster
0:27:38 > 0:27:40when it comes to accidents on rail tracks.
0:27:40 > 0:27:42Let's face it,
0:27:42 > 0:27:45there are only two places you should be on the railway -
0:27:45 > 0:27:49safely on the platform or on the train.
0:27:49 > 0:27:53Even with Crossrail and possibly HS2 coming on stream in the future,
0:27:53 > 0:27:57our existing system will continue to be put under huge pressure
0:27:57 > 0:28:00as passenger number increases.
0:28:01 > 0:28:03The one thing we do know is that
0:28:03 > 0:28:05passenger numbers are set to increase,
0:28:05 > 0:28:08but with the right investment and the right technology,
0:28:08 > 0:28:12the trains will run on time, most of the time.
0:28:16 > 0:28:19Next week, Bang is asking if science can offer any relief
0:28:19 > 0:28:23as the refugee crisis in Syria worsens...
0:28:23 > 0:28:25In the meantime, to find
0:28:25 > 0:28:28out about careers in the railways check out the website at /bang.
0:28:28 > 0:28:31And to find out more about the science of rail,
0:28:31 > 0:28:35follow the links to the Open University's interactive pages.