Executive summary
Three linked innovations are proposed:
- By reducing emergency stopping distances, more trains can use the existing tracks Eddy current brakes (as currently used on German high speed railways) will significantly reduce the emergency braking distance for fast moving trains. However, instead of laying new steel tracks, as required by the German system, additional iron rails will be added in parallel with the existing steel tracks.
As an interim measure, network capacity could be increased by adding eddy current brakes to existing rolling stock. Then, as demand increases, new rolling stock incorporating Innovation B could be introduced on the busier lines. - Further increasing network capacity by building new rolling stock
This is where the new iron rails will gain an advantage over the German steel rail system.
A magnetic traction system (MagTrac) that will allow trains to accelerate more rapidly without losing traction on steep, greasy or iced up tracks. The braking will be superior to eddy current braking at low speeds. New rolling stock will be required. - Using AI to create a Transport Internet (Year 2040?)
After implementing innovations A and B, the railway network will become a lot more flexible, in a manner that is analageous to the flow of information around the internet. Guided by artificial intelligence (AI), driverless rolling stock will travel around the UK (and eventually Europe) network, reducing the amount of goods traffic on our roads.
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Executive summary 2: Technical details
Innovation A: Eddy current braking
Eddy current brakes are similar to normal friction brakes in that they convert the kinetic energy into heat. But, the heat is spread out over a long rail instead of being concentrated on the friction (brake) pads.
They offer shorter stopping distances than friction brakes and are unaffected by leaves, ice or snow on the tracks. Thus, more trains could run on the same length of track, without increasing the risk of crashes. This would increase the potential profitability of the network, because more income could be earned from the existing infrastructure.
Fundamentally, eddy current braking is not new because German high speed trains have been using eddy current braking since the 1990s. The German system induces swirling electric currents in the same rails that the trains run on. The system works well, but the rails have to be pre-stressed when they are laid, in order to prevent them buckling when the eddy currents warm them up.
In order to gain the benefits of eddy current braking on all railway tracks, the cheapest option is to add two extra metal rails, specifically for eddy current braking purposes.
In principle, any electrically conducting metal would be adequate, but with Innovation B in mind, iron rails will be required.
Figure 1. The iron rails are laid in short lengths of (say) 2 metres, with small gaps being left between successive rails. Far larger gaps are required to prevent fouling in the vicinity of points and level crossings.
Eddy current brakes are very effective at high speed but they lose braking power at low speeds because the eddy currents are weaker. So, conventional friction brakes are still required to bring the train to a final halt.
The succeeding generation of trains fitted with Innovation B will not suffer from reduced braking power at low speeds.
Note This is only an illustrative example of an eddy current braking mechanism, other brake designs are already in use on some high speed train systems. The real innovation that is being proposed is the addition of iron rails, in anticipation of a future generation of rolling stock incorporating Innovation B.
Innovation B: A Magnetic Traction system (MagTrac)
(i) This arrangement illustrates the electromagnetic principles involved, but it only allows limited movement.
Figure 2. The platform (representing the rolling stock) moves in accordance with the basic law of magnetism that, ‘Like poles repel and unlike poles attract’.
Movement is limited by the need for an iron cross-member, for the magnetic flux to pass through.
(i) Iron rails rather than steel are specified because they have superior electromagnet properties. (They are easier to magnetise and demagnetise.)
(ii) In order to allow unrestricted movement, along the track, the cross-member is moved below the rails and the solenoids are replaced by ‘half solenoids.’
Figure 3. The exposed ends of the iron U-bar are buried to prevent them attracting magnet debris. Ideally, if space allows, the iron rails are placed outside the steel rails in order to provide additional stability in cross winds and when taking bends at speed. However, the traction mechanism will be equally effective if the iron rails have to be placed between the parallel steel track rails.
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nnovation C: A Transport Internet (Say for the year 2040)
The superior braking and accelerating features of Innovations A and B will allow heavy goods trains to enjoy similar braking and accelerating performance to passenger trains.
In the long term, this flexibility will allow driverless trains to move goods or passengers between any two points on the network, with artificial intelligence (AI) being used to choose the optimum route for long journeys.
For example, shipping containers could be transported from say Perth in Scotland and Swansea in Wales by a number of routes, some of which involve containers switching trains along the way..
Figure 4. Business customers could be offered different types of delivery service, depending on whether they require prompt delivery or minimum transport costs.
In order to increase the number of nodes where containers can be switched from one train to another, additional goods yards will be required, each equipped with cranes or other technology that will allow containers to be transferred in minutes.
The railway network has been functioning as a crude form of transport internet since the nineteenth century. However, this title will be more appropriate in the future, thanks to the use of artificial intelligence to find optimum routes in the complex conditions created by high traffic densities on the lines.
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A more detailed discussion of the innovations
Invention A: Easing the railway capacity problem in ten years, without adding new lines
A1 The engineering problem to be solved
Railway train wheels have a poor grip on steel tracks, compared with rubber tyres on roads. This severely reduces the ability of trains to brake rapidly during an emergency.
For example, at 80 miles/hour, the braking distance for an eight carriage passenger train is sixteen times the braking distance for a car travelling along a dry road at the same speed.
In the era of driverless vehicles, the “thinking distance” will effectively be eliminated. This will make the contrast between road and rail breaking distances even greater.
To meet an increased demand on the national railway network, we can either
(a) Stick with our Victorian era friction braking systems and build more tracks to increase capacity. - This is the HS2 approach.
OR
(b) Employ a powerful frictionless braking system that will allow more trains to travel safely along our existing tracks. This would allow the whole of the UK to benefit from improved rail communications.
The powerful brakes we need are are already up and running in Germany. They are called eddy current brakes.
Eddy current brakes –a short primer
Roller-coasters and German high speed trains have an important feature in common. They both use eddy current brakes to slow them down.
The principle behind eddy current braking is that when a metal object, for example a metal bar moves through a magnetic field, swirling electric currents called eddy currents are generated inside the bar.
There are two consequences that you need to know about:
(i) The eddy currents heat the bar so that it can become very hot,
(ii) The bar experiences a backwards force that tries to slow it down.
The engineering appeal of eddy current brakes is that they convert the kinetic energy of a moving train into heat without the moving parts coming into physical contact. So there is no wearing out of the parts due to friction.
As a bonus, ice and wet leaves on the track do not impair braking.
An eddy current braking system for trains has two essential ingredients: a set of magnets suspended from the train to create the magnetic fields and bars or rails along the track to host the eddy currents.
The German high speed train system uses the track that the trains run on for eddy current braking. Unfortunately, the heat generated during braking causes potential buckling problems. The Germans have got round this by laying new tracks, where the heating is allowed for.
We propose a quicker and cheaper retro-fitting solution to the problem; laying a second set of rails on the existing sleepers, purely for hosting the eddy currents.
As you will discover in the second article, laying the additional rails could be an excellent long term investment for the UK economy because they will become the foundations for a revolutionary new Transport Internet based on MagTrac Technology.
Limitations of all forms of electromagnetic brakes
The slower the train is moving, the lower the strength of the eddy currents. Consequently, traditional friction braking systems are still required for bringing slow moving trains to a halt.
A2 How the improved British braking system will work
In addition to existing brake systems, each carriage will be fitted with eddy current brakes that automatically slow the train down if a dead man’s switch is operated.
We recommend that the new “braking rails” are made from iron, so that the track is ready for running MagTrac trains at a future date.
Figure 5. For routine braking, the electromagnets can be powered by an onboard generator. But for maximum protection, backup batteries would be provided. Each magnet would be serviced by its own battery.
The total braking contribution made by the eddy current brakes increases with the number of magnets.
Sufficient magnets could be added (for example), so that, with 50% redundancy, the train carrying capacity of the line could be doubled without compromising braking safety.
A3 Anti-fouling measures
(i) The working height of the magnets is fixed relative to the (non-rotating) axle casing rather than the chassis. This decouples the magnets from vertical movements of the chassis.
(ii) The magnets are positioned higher than the running rails and there are no eddy current braking rails in the vicinity of junctions, points or level crossings.
(iii) Certain novel anti-fouling mechanisms have been deliberately omitted from the above diagram, in order to allow any organisation choosing to develop Invention A to file for patent protection.
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Keeping the rails clean
scavenging electromagnets and brushes ahead of the brakes would keep the iron rails clear.
A4 Delivery time
Eddy current braking is a well developed technology, so R&D time will be minimal.
Time will be required to lay the iron rails and build new rolling stock fitted with eddy current brakes.
The first improved capacity lines could be ready within five years.
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Where do we start?
Bill Courtney is a Manchester man who supports the idea of a northern powerhouse. He suggests that we learn our new track laying skills on a relatively quiet northern line, for example the one between Chester, Altrincham and Manchester.
[The journey from Chester to Manchester includes 15 station stops. So, if improved brakes cut 30 seconds off the average traveling time between each station, the full length journey time would be reduced by 7.5 minutes. In general, commuters would see their travel times reduced, without the trains having to travel any faster.
We could then give a rocket boost to the north by upgrading the trans-Pennine route from Liverpool to Hull in two phases.
The worlds first passenger train powered by "Rocket" started in Liverpool and ended in Manchester. It would give a great lift to British engineering if we Brits launched a new Rocket 2 railway age.
Lets go for it!
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Invention B: MagtTrac
Introduction
Invention A, eddy current braking is suggested for commuter routes where the trains make frequent station stops. Its primary aim is to reduce stopping distances so that more trains per hour can run on the track without compromising on safety.
MagTrac also offers improved braking, but in addition it offers higher speeds and greater resilience against traction problems such as ice or compacted leaves on the track.
Superior traction will allow MagTrac trains to climb far steeper gradients than convention trains.
MagTrac can also provide stability when taking bends at speed, but without the train having to tilt.
This will provide future proofing for the network. If we wish to add new railway lines we will have the option of building them overhead, above existing motorways and roads. This will allow the network to be expanded without the massive land purchase costs involved in building HS2.
For environmental reasons, MagTrac trains could be run on hydrogen fuel. This will eliminate the costs currently associated with electrifying inter-city routes.
Alternatively, Latent Power Turbines installed in the roofs of the carriages could provide power.
Background: Another British invention, Maglev was our inspiration for Magtrac
Maglev trains are hover trains. They were invented in Britain in the 1960’s by Professor Eric Laithwaite and are now running in China.
They offer several advantages: Wear on the track is minimal and acceleration, braking and fuel economy all improve,
but these benefits are outweighed by the high track building costs.
MagTrac is our proposal for gaining many of the benefits of Maglev, but at a small fraction of the capital cost.
Our design breakthrough
We reduce costs by mounting the electromagnets on the trains instead of the tracks.
The electromagnets are suspended under the train and interact with soft iron rails mounted on the existing railway track sleepers.
("Soft" is used in the electrical engineering sense, meaning the rails are easy to magnetise and demagnetise.)
The braking and acceleration benefits of Maglev are maintained, but MagTrc’s levitation effect is not sufficient to support the weight of the train.
Figure 6, Magtrac.
Q. Why are iron rails required instead of steel?
A. Iron rails are better at amplifying the strength of the electromagnets than steel/. But they rapidly lose their magnetism when the train passes. This is good because it eliminates the problem of steel cans and other ferromagnetic junk sticking to the rails.
HOW IT WORKS
We will build the MagTrac principle up in stages
B1 The key concept
First we consider what happens when an electric current is passed through two solenoids resting on a soft iron bar.
[A solenoid is a cylindrical coil of wire that acts as a magnet when an electric current passes through it. The magnetic effect is weak if the interior of the solenoid is filled with air, but strong if the air is replaced by iron.]
The solenoids become electromagnets and either mutually attract or repel, depending on their polarities.
Figure 7. In addition to attraction or repulsion between the two solenoids, each solenoid experiences a repulsive force between itself and the enclosed soft iron bar. This provides a small levitation effect.
The law of conservation of energy has to be respected so we do not get "free" energy out of either of these arrangements. For example in Fig. 6 (a), after the solenoids have moved together, work has to be done against the magnetic attraction, to restore the magnets to their original positions.
We can't cheat nature by switching the magnets off and then moving them apart because when we switch the magnets back on again work has to be done against the back EMFs as the magnetic fields are rebuilt.
B2 A load carrying platform
Plan view:
Figure 68 To move a lightweight platform along a short length of track, the soft iron bar needs to be bent into a U shape.
B3 A practical traction unit
For the platform to move along a track of indefinite length:
(i) A long chain of U shaped iron bars is required.
(ii) “Half solenoids” that can “jump” from one iron bar to the next are used.
Figure 9. The platform and supporting half solenoids can move along an indefinite length of track
Figure 10. This is a “half solenoid”, with all of the windings connected in parallel. When an electric current flows through the windings, a magnetic field similar to a full solenoid is produced. But its asymmetry results in a net upward force on the half solenoid.
Figure 911 An alternative, series winding. The neutralising effect of the upper half solenoid is minimal, because of its greater distance from the soft iron rail.
Figure 12. Further details of the electromagnetic coupling.
The upthrust is a useful bonus but it cannot be relied upon to support the weight of the train because it varies with the current passing through the half solenoids.
The upthrust on the train produces an equal and opposite down thrust on the iron rails. This improves the friction grip between the iron rails and underlying sleepers.
We will refer to the activated half solenoids as runners and the lengths of soft iron tracks as stators.
It is not necessary for the runners to be in close contact with the stators and large clearances between them are possible to avoid fouling by small items of debris. (Large clearance gaps require large diameter half solenoids. So the total length of conducting wires generating the magnetic flux increases, compensating for the larger air gap.)
Large clearances will allow wipers to be added, to periodically clean the under surfaces of the runners.
The conducting wires can be made from superconducting material and the half solenoids immersed in very cold chambers protected by Dewar insulation.
B4 Explanation: Why the size of the air gap, ice and leaves on the rails do not affect performance
Figure 13.
Icing of the iron rails will be a rare event because MagTrac has a natural built in de-icing mechanism.
When an iron rail goes through a magnetisation-demagnetisation cycle, a small amount of heat is generated. (Hysteresis loss.) This will help to melt any ice or snow in winter.
The only downside of a large air gap is that the half solenoids are slightly bulkier, heavier and more expensive to build.
Q. How effective will MagTrac braking be?
A. Braking and traction increase with the total number of turns in all of the half solenoids, the currents passing through the wires and the cross section area of the iron rails. In principle, Magtrac braking could be as efficient as the braking on a Formula One racing car. In reality, a far more modest braking system should meet commercial, safety and customer needs.
As with eddy current brakes, MagTrac braking power increases with train speed. But the reverse is also true; they cannot bring the train completely to a halt. Traditional friction brakes will be required to finally bring the train from a slow walking speed to a halt.
B5 Reducing stray magnetic fields
Stray magnetic fields can attract ferromagnetic debris such as nuts, bolts and nails. A number of steps can be taken to design this problem out of the system.
B6 Superconducting shields
For superconducting systems the runners are lodged in cold chambers. Magnetic flux cannot penetrate a sheet of superconducting material, so by lining the out facing walls of the cold chambers with superconducting material, magnetic flux shields can be created.
Figure 14. Superconducting shielding.
To prevent the outer faces of the Dewar flasks icing up in winter they can be fitted with heating elements to keep their temperature just above 0oC. Alternatively, anti-icing coatings can be added.
Miniature "cattle fenders" and scavenging electromagnets can be added ahead of each item of rolling stock to prevent damage by small items of debris.
B7 Burying the soft iron magnet poles also reduces stray magnetic fields
Figure 15. A vertical cross section at track level.
B8 Keeping the runners and flux shields cold
Runners and flux shields can be chilled using liquefied gases or dedicated refrigerators. A combined system may be best.
New designs of cryocoolers (low temperature refrigerators) created for use with rolling stock are published on our superconductors and cryocoolers web page.
B9 Powering Magtrac trains
If the electromagnets are superconducting there are no heat losses but energy still has to be expended driving the electric currents against the back EMFs produced as the train moves.
Electrification using overhead power cables is one option. But upgrading existing diesel lines is very expensive because bridges and tunnels have to be modified to allow extra height for the electricity cables.
MagTrac can eliminate this cost by using onboard liquid hydrogen as the fuel, with the fuel being used twice. First in liquid form, as a superconducting cable coolant; then as a fuel to generate electricity.
To burn the hydrogen fuel efficiently onboard, fuel cells, four stroke engines or Latent Power Turbines can be used.
Liquid hydrogen fuel safety
The Hyundai Tucson Fuel Cell SUV runs on liquid hydrogen. It has successfully completed legislative crash tests. https://www.hyundaiusa.com/tucsonfuelcell/
B10 The copper alternative to superconducting windings
The argument in favour of superconducting windings is that they eliminate electrical resistance (Joule) heating losses. Copper is not a superconductor at liquid hydrogen temperatures but its resistivity is les than 5% of its value at UK average weather temperatures. If copper is used for the windings there will still be some Joule heating losses at low temperatures but the thermal energy can be used for warming the hydrogen prior to its use as a fuel.
Copper is easy to handle when manufacturing the half solenoids and has the safety bonus that it can still be used for effective braking, even if the hydrogen cooling system fails.
B11 Regenerative braking
As we have explained above, to produce motion an electric current must pass through each pair of half solenoids on the same part of the track. If the current supply through one of the pair is switched off, then the motion over the soft iron rails will induce an electric current in the other. But energy cannot be created or destroyed; it can only change from one form to another. To conserve total energy as electricity is generated, the train must lose kinetic energy by slowing down. The electricity generated by the second half solenoid can be used to charge a battery or super capacitor for later use. Alternatively, it can be dissipated into the environment as heat using electrical resisters.
Electromanetic braking is not very effective at low speeds. So, conventional friction brakes will still be required to bring the train to a final halt.They will also be needed and to prevent stationary trains rolling down hills.
B12 Remote braking On the approaches to potential accident spots such as railway crossings, active Magtrac rails can be installed. These would include externally powered solenoids that converted attraction into repulsion. This would allow remote braking by an external operator or an intelligent CCTV system.
Figure 16. Active MagTrac rails include current carrying solenoids that can be switched on remotely. These instantly convert traction power into braking power.
Braking solenoid off: Axle casing mounted N attracts second 1/2solenoid axle casing mounted S. Traction power is generated.
Braking solenoid on: Axle casing mounted N repelled by Magtrac rail mounted N. Braking power is generated.
If the track based system detects that the trains half solenoid currents have been changed to initiate braking, the track solenoid current can be switched off.
The UK mainline Health and Safety report for 2012 records four pedestrian and five car deaths on level crossings.
This design can also provide protection for maintenance staff Portable half solenoid versions of the the remote braking system could be installed on lengths of track where maintainable work is being carried out while the track is still in use.
Points
There would be no Magtrac iron rail in close proximity to points. If necessary, axle coupled motors would be used to shift stationary trains away from these sections.
B13 Noise reduction bonus
The reduced wheel on track loading, thanks to the MagTrac up-thrust, will reduce train noise.
MagTrac and eddy current braking both eliminate the squealing of friction brakes and the vibrations caused by uneven wear on the steel tyres resulting from friction braking.
B14 Dissipation of kinetic energy during braking
Under normal braking conditions, the kinetic energy lost as the train slows down would be used to generate electricity and then stored in batteries, super-capacitors or flywheels. During emergency braking, some electricity could be used to boil water, which would then be vented off as steam.
B5 Stability on bends
The iron rails are depicted as being located inside the steel runing rails. Alternatively, they can be placed outside the steel rails. This would offer extra stability on bends, especially if the solendoids above the iron rails on the outside of te bend temporarily carried a higher current and produced a greater upthrust.
B16 The Business Argument: Magtrac vs. HS2
HS2 requires entirely new tracks to be laid.
(i) Land has to be purchased and existing landowners compensated.
(ii) New bridges, tunnels embankments and cuttings need to be built.
In contrast, Magtrac only requires additional soft iron rails to be added to existing tracks.
We don’t know how the development of driverless cars, internet conferencing and other technologies will affect inter-city train demands in the future. Magtrac is a far safer bet than HS2 because rolling stock only needs to be upgraded from eddy current braking to Magtrac standards if there is clear customer demand.
B17 Outline timetable for decision makers [MagTrac + eddy current braking]
Eddy current braking
The MagTrac rails can be used for eddy current braking, as described in the first article. If we act promptly, eddy current brakes could start improving network capacity within five years.
During the first year of research and development (at least), eddy current and MagTrac systems are developed in tandom, to ensure that the the iron rails are compatable for both.
The full Magtrac system
Within six months
An industrial research lab completes the basic proof of concept experiments as illustrated in Figure 6 above. The experiments are repeated using half solenoids.
End of first year
A copper wire based MagTrac locomotive unit is running on a short length of narrow gauge rail.
Preliminary estimates relating to the design and costs of the iron rails are made.
Three years
A hydrogen cooled and fuelled system is operating and the locomotive unit is running for long periods on a closed loop of narrow gauge track.
Iron rail laying and other costs are firmed up.
Eight years
A demonstration full scale MagTrac public service is in operation.
Perhaps Manchester to Liverpool....?
Twelve years
Rolling stock on London to Birmingham line upgraded to Magtrac standards..
Fifteen years
Roling stock on Birmingham to Manchester, Sheffield and Leeds lines upgraded. Followed shortly afterwards by upgrades to extensions to Glasgow and Edinburgh.
2030
All major UK and Northern Ireland rail rou upgraded to include eddy current/MagTrac rails. The Republic of Ireland adopts eddy current braking/Magtrac, building stronger trade relations across Ireland.
This timetable is flexible
The rail routes that are currently experiencing the greatest capacity problems can be upgraded first.
"According to Network Rail figures produced two years ago long distance trains coming into Euston are only 60% full during the morning peak. This contrasts with Paddington, where trains are 99% full and Waterloo, where the figure is 91%." (Daily Telegraph 10 September 2013.)
(iii) Compared with HS2, more people and businesses will benefit
Figure 17. At its best, HS2 will bring prosperity to a few English cities by 2032.
But, the nation as a whole will be paying taxes to fund this.
Figure 18. MagTrac is a far cheaper alternative per mile that will help to stimulate the whole UK economy.
(iv) The manufacturing & export bonus
HS2 is an engineering dead end because we will be copying high speed systems developed abroad. In contrast, Britain will be the world leader in developing combined eddy current braking and Magtrac. This will generate massive engineering export opportunities for the UK.
(
v) Attracting young people into engineering
The Japanese bullet train was running two generations ago, so HS2 is "ancient" engineering in the eyes of youth. In contrast, combined eddy current braking and MagTrac is new and British.
The development of MagTrac falls into a series of short visually interesting steps. The R&D project could have its own website with videos of test runs being posted on U-Tube. Young British engineers [hopefully having a representative gender and ethnic mix] would be used as the media face for the project.
An engineering science teacher should form part of the team. They would pose engineering problems and suggest student projects linked to the MagTrac development. Links to relevant project equipment suppliers would be provided.
Invention C – A Transport Internet for the 2040s
Driverless cars will eliminate the tedium of driving for many and will allow those who are currently barred from driving for medical reasons to travel by car alone.
Unless we act boldly and imaginatively, these benefits will inevitably lead to an increase in traffic on our roads.
We propose minimising this increase by enabling cars and lorries to make part of long journeys by rail using a transport internet.
The following example suggests how any car, driverless or conventional, car could use the transport internet to travel from Crieff in Scotland to Swansea in Wales.
Figure 19. A motorist using the transport internet to travel from say Crieff in Scotland to Swansea in Wales might have the choice of two embarkation stations, Perth or Dunblane and several routes through England. The routing software would suggest fastest and lowest cost options. The computer analysis would be utilitarian; offering the fastest/cheapest services to the greatest number of travellers.
Driverless vehicles could move themselves between trains. Conventional vehicles could enjoy the same advantage if their front wheels were mounted on driverless robot trolleys for the journey.
Freight containers would make transitions between trains on driverless wheeled pallets.
The bulk of domestic and European freight could be shipped overnight via the transport internet.
The transport internet concept could only become viable if the capacity of the whole of the rail network was significantly increased by using eddy current braking and MagTrac technology.
If the demand exceeds the capacity of the existing network, new lines could be added, but unlike HS2, this will not require the large scale acquisition of new land.
MagtTac trains will be able to climb far steeper gradients than existing trains, allowing new train line to be built over existing motorways, climbing higher to clear bridges and other civil engineering features that straddle our motorways.
MagTrac can provide traction power to individual passenger carriages or vehicle carriers. If this is combined with driverless train technology, passenger, vehicle and goods carriers will be able to travel as individual units. This will greatly increase the choice of destinations available from each embarkation station and minimise the number of train swaps that need to be made on long journeys.
be necessary
In the era of driverless cars and goods transport vehicles, the free market incentive for vehicles to travel long journeys by rail will be low. However, in order to reduce road congestion, this shift to rail will be necessary.
To fund the transport internet, a mileage charge could be made on all vehicles using our roads. This would be used to subsidise train fares for vehicles using the transport internet alternative.