Hyperloop: getting there faster

By David Layzelle

The 20th century has bought us some magnificent advances in the world of vehicles and transport.  From aircraft and helicopters to submarines and ships that traverse the oceans with ease, to land vehicles that have become correspondingly faster, safer, and more reliable.  Rail travel has been comparatively stable with changes including the switch from steam to diesel and electric power. It is this field which is likely to see one of the biggest advances as we progress into the 21st century. Stand by for Hyperloop systems and the ability to cover huge land distances in a fraction of the time it currently takes, either by land or even air transport!

The aircraft industry has been twirling hypersonic craft in front of us of a couple of decades now, but many oproposed systems remain in development.  The French TGV and Japanese Bullet trains seem like the starships of the train world, but the blistering possibilities of Hyperloop transportation systems will represent a significant step change.  Hyperloops’ aren’t just some vague possibility. With plenty of groups working on real applications, the first examples of practical systems are already well in to the planning and advance development phase. 

Floating Trains
The premise behind Hyperloop transport is one of contact-less vehicles running in the soft vacuum of sealed tubes and potentially reaching speeds approaching 1,000 kilometers per hour.  Much of the technology already exists to some degree, and a fully working system is only barred by engineering practicalities and a scaling up of prototype designs.  The Hyperloop principles being investigated use two different cushioning systems; magnetic levitation – Maglev – and an air cushion.  Maglev is existing technology and there are several working systems, notably the Shanghai Maglev which operates commercially, though is considered only low speed as it averages just 140 mph on its six minute journey connecting Shanghai Pudong International Airport and the outskirts of central Pudong where passengers can catch the Shanghai Metro to all parts of the city.  The air cushion system is currently under consideration by Elon Musk’s SpaceX Corporation and the Hyperloop name is in fact a registered trademark of the group in some countries.

Maglev systems have been shown to work in relatively low speed designs and come in two basic technologies; electromagnetic suspension and electrodynamic suspension.  The electrodynamic type uses a series of superconducting magnets which switch polarity in unison with complimentary electromagnets on the train pod, and is designed to aid acceleration and keep the train steadier at high speed.  However, since the system is designed to run in a partially evacuated tunnel, there is little chance of anything such as a breeze or a bird strike upsetting the balance of the train as it travels at ultra-high speed. 

Technical Issues
In theory, Hyperloop trains have little in difference to their underground train cousins, but there are certain technical aspects that have to be ironed out before a usable and safe commercial system can be built.  Top of the list is the track system which differs significantly from current track types.  In fact, the Hyperloop cannot ever run on conventional train tracks, regardless of the type of levitation used, so the construction of a suitable track system is the greatest priority.  All designs for Hyperloop systems currently under investigation feature overhead tubes supported by pylons, which is both cheaper and easier to maintain than buried systems. 

Many of the proposed systems required super cooled magnets to operate at their optimum speeds, but with the liquid nitrogen needed to run such magnets being cheaper than milk weight for weight, that too is no longer an issue. For over ground systems there is no need to burrow deep into the earth, making a network of connected Hyperloop systems practical and cost effective. 

The actual pods on proposed systems are also much smaller than current train carriages.  This is because long trains would require huge amounts of energy to start them in motion, whereas short sections will accelerate up to high speeds quickly.  A further issue is that despite the pods running in partial vacuums there is still concern that a pressure wave will build up in front of the trains. This has been countered in current designs by placing a large fan at the front of the pod which transfers air to the rear of the train and prevents the pressure wave.  So technically, Hyperloops are a distinct possibility right now.

But is it Safe?
One of the main concerns about Hyperloop systems is how can we be sure that a vehicle travelling over ground at potentially several thousand kilometers over hour will be safe?  There have been several criticisms of the Hyperloop concept, not least because of its potential vulnerability to shifts in the ground which might lead to drift in alignment.  Some of the first Hyperloop systems are being built in California. With its well-known geological feature the San Andreas Fault, this could become a major issue should an earthquake strike.  However in reality, the engineering of systems would address the need for a steady track into account and plan methods of ensuring that it remained so, regardless of how shaky the outside world became. 

Psychologists have also questioned the effects of the experience on passengers.  Sitting in a small windowless pod travelling at what could finally be extremely fast may become unduly unpleasant or possibly even frightening for passengers.  It is also likely that a Hyperloop pod could accelerate at potentially tissue-damaging speeds as an added problem.  Furthermore, with many miles of sealed tube systems, were a breakdown and stoppage to occur, getting the passengers out could become a significant task.  Plainly, there is a lot of work to do yet. 

Coming to a Sealed Tube near You soon……Probably
Most of these are issues represent normal engineering problems rather than being issues of theoretical physics and are not insurmountable, so it is likely that prototype systems are not too far away.  The mathematics behind the systems are understood, the materials and components all exist, and there are no real barriers to proving the technology, so expect to see the first systems coming on line within the next few years.    

Hyperloop technology is a step change in transportation and akin to the introduction of jet engines to air flight, and is tantalizing in the realization that it offers the possibility of travelling huge distances quickly, and that can only be good.