Dr. Zev

How the Tragedy in the Bronx Would Not Have Happened with MagLev

Dec 08, 2013

This commentary discusses the various ways that use of Magnetic-Levitation (MagLev) in standard-speed rails could have avoided the the recent derailment of a commuter train in the Bronx, New York City.  It also discusses the technical aspects of adding Danby-Powell MagLev equipment to existing rails.


A week ago, 2013 December 1, a commuter train, in the Bronx, New York City, rounded a curve at full speed (82 mph), being pushed by its locomotive.  Half the cars flew completely off the tracks, and the rest of the cars, inclduing the locomotive, derailed but remained atop the track bed.  This tragedy in the Bronx resulted in four deaths, and dozens of injuries.  This could have been avoided by using an extant technology called PTC (“Positive Train Control”) [1], which was promulgated almost four years ago and is scheduled to go into full effect in late 2015, in about two years.  It is still very controversial.

What I wanted to discuss here is how a Magnetic-Levitation (MagLev) commuter train would have avoided this collision in the first place, plus provide a slew of other benefits.  This goes well beyond what PTC has to offer.  Basically, safety is built into such MagLev systems,

What Happened

I will try to reconstruct what went wrong, based on what I’ve read read in the media, and my own experience and knowledge, with a little help from family and friends.

Current news reports indicate that the motorman may have “zoned out” — that is, fallen asleep at the “switch”.  The train was rapidly approaching a sharp curve right before a station.  The only ways to slow or stop the train would be or the motorman to apply the brakes, or for some central control authority to cut the power.  It is possible that, if the motorman was in a control cab in the forward passenger coach (as I assume he was), that there might be another crewmember in the locomotive, at the back of the train, but is is unclear if there is such a crewmember, or whether he’d have any authority to stop the train [2].  On Friday, the National Transportation Safety Board (NTSB) ordered Metro-North to have a second crewmember at the controls of the train any place where the speed limit changes by more than 20 mph.

Apprently, the motorman’s has signals in his cab [3] to tell him what to do, but these do no good if he’s asleep.

The train consisted of seven passenger coaches, and one locomotive that was pushing the coaches.  The reason for this unusal configuration is that there is not enough space at Grand Central Terminal to turn the train around, so that the locomotives are always at the northern end of the train, whether it is moving northbound or southbound.  (Grand Central Terminal is the train’s southern terminus in Manhattan.) [2]

The train originated in Poughkeepsie, and the line isn’t electrified until it gets to Croton-Harmon [2] [4].  Therefore, the train cannot be composed of self-propelled rail coaches (such that each coach is propelled by its own traction motors powered by electricity from the third rail), and must have passive coaches pulled or pushed by a locomotive.  (At the point of the derailment, the locomotive was powered by electricity.)  Pushing a train into a derailment is more dangerous than pulling a train that derails, because pushing the train can cause it to jackknife.

The fact the the train was being pushed, rather than pulled, just made a bad situation worse.  The proximate cause was inattention by the train’s driver.  An automatic system, such as PTC (“Positive Train Control”) [1], could have assisted the driver and avoided this tragedy.

What Would Have Happened if This Were a MagLev Train?

Usually, one thinks of Magnetic Levitation (MagLev) as being for rail vehicles that travel a prop-plane speeds, about 300 mph.  Certainly I myself have been pushing this high-speed MagLev [5].  However, the originators of Superconducting MagLev, Drs. Gordon T. Danby and James R. Powell, and their associates, have devised a means to use MagLev, with all its advantages, on lower-speed trains.  They know how to add Magnetic-Levitation rails to conventional rails so that both kinds of vehicles can use the same rail bed, but not at the same time.  This can be done by adding special plates to the railbed.  This is written up in their recent book, Maglev America [6].  In fact, it takes up about half the book!

The train in question had been traveling at 82 mph in a 70-mph zone, and continued to travel at that speed when the limit dropped to 30 mph.  The centrifugal force threw part of the train completely off the track bed, and the locomotive (in back of the train) helped push them off even more.

If this were a MagLev train, a Traffic-Control Center (TCC) would always, and automatically, keep the train at its prescribed speed.  Even if the train were going around the bend at 82 mph, the remarkable stability provided by MagLev would have kept it on the track, but might have jostled the passengers pretty badly.  The train is propelled by its own portion of a Linear Synchronous Motor (LSM).  The LSM’s power comes from the rail, under the control of the TCC.

How Commuter Rail is Helped by Using MagLev

In summary, the advantages of MagLev for commuter rail are:   (after [6] p. 258)

  1. Shorter travel time between stations.
  2. Smaller but more-frequent trains in off-peak time.
  3. A cleaner, more efficient ride.
  4. Much lower operating costs, fares, and government subsidies.
  5. More ridership, and thus better capital amortizing.
  6. A more comfortable ride.
  7. Automatic control of speed and braking but still with an on-board “train driver”.
  8. Phenomenal stability.
  9. Practical immunity from the weather.
  10. Much shorter stopping distance.
  11. Continued compatibility with conventional rail.
  12. Can still run freight trains.
  13. Modest cost of $4 to $6 million per 2-way mile.

Many of these advantage also apply to high-speed (300 mph) MagLev.

Expanding these thirteen points:

  1. Because of the ability of MagLev to accelerate and decelerate smoothly and comfortably, the travel time between stations, and thereby the overall travel time, will be shorter.
  2. With each train “riding the wave”, the “wave” being generated under the control of the TCC, and not needing a massive locomotive, the trains could be smaller, resulting in more trains and shorter wait times between trains.  This is particularly important at off-peak time, resulting in more frequent service, especially late at night; and less of a penalty for riders of “missing the train”, making it more likely that off-peak travelers will choose to go by rail.
  3. MagLev uses less electricity than conventional electric traction.  This means reduced indirect (power-plant) emissions.  There are no direct emissions.  In addition, conventional rail generates a considerable amount of steel dust from the wheels and rails, and asbestos dust from the brakes, which can be a health concern, particularly for underground operation, and many commuter rail lines operate at least partly underground.  None of this is generated when using MagLev mode.
  4. Much lower operating costs, resulting in lower fares, and much lower government subsidies.
  5. With lower fares and better service, more people would use commuter rail, amortizing the capital costs over a greater base.
  6. A more comfortable ride, in that, in MagLev mode (above ~15 mph), there is no swaying, no vibration, no clickety-clack, and no jerking.
  7. Instead of having a highly-trained motorman who controls the speed and braking of the train, these functions are handled by a Traffic-Control Center (TCC), with the “train driver” there to apply the emergency brakes when needed, and to take care any other unusual situations that may arise.  This way, there is no room for human error, but there is space for human insight and intelligence when needed.  This will slightly increase operating costs, but less than the other savings.
  8. Phenomenal stability in all directions (pitch, roll, yaw, and lateral) except for, of course, the direction of travel itself ([6] p. 238).
  9. Practical immunity from the effects snow, ice, rain, and fallen leaves, as long as they aren’t as thick as the minimum 4" MagLev clearance.
  10. Much shorter stopping distance (400'-600', vs. 3000'-5000' on conventional rail) ([6] p. 239).
  11. There will be continued compatibility with conventional rail, as the standard-(Stephenson-) gauge (4'8½") steel rails will still be there.  They are still needed by the MagLev trains for low-speed (less than ~15 mph) operation.
  12. We can also run freight trains, whether MagLev or conventional, on the same rail line, without the heavy freight trains misaligning the passenger rails, which can ruin the comfort for the passengers.
  13. The price of all this is only $4 to $6 million per two-way mile ([6] p. 238).

Why are Danby and Powell Empasizing Lower-Speed MagLev?

By no means are they abandoning high-speed MagLev.  They have been frustrated by politicians who should be funding research into their very-promising new technology of second-generation MagLev for 300-mph travel; but instead plan to waste the public’s money on conventional, steel-wheel-on-steel-rail, High-Speed Rail (HSR), such as the proposed “national” HSR system [7] and the similar California system [8].  These are just the latest tweaks to a two-hundred-year-old technology that ought to be put to rest!

Instead, these engineers recognize the political realities, and it is better to take one step back to take two (or three, or four thousand) steps forward.  They write:

“…Danby and Powell… knew that replacing existing infrastructure would be resisted ….  It is difficult to replace old technology with new technology, … but if it becomes necessary to disable an old system while you are installing a new system, the resistance to change becomes overwhelming, and the old system prevails.  The best way to introduce a new transportation system is to recognize that the old technology must be able to do all or most of what [it] has been doing all along, while creating the new.” ([6], p. 223)

I see the above quote as being a very sad commentary on the ossification of America.  When we were a young country, we could put new canals and rail lines wherever it was natural to put them, and not worry much about opposition from established stakeholders in the old system, because the old system was conestoga wagons traveling on dirt roads.  Now, America is so crowded that we have a tough time finding the rights-of-way for new transportation systems, and we also have opposition from existing stakeholders.  Old age should not be a barrier to innovation.  Danby and Powell are both octogenarians, and their creative juices are still flowing strong.  Many of the other people involved in MagLev. including the other authors and contributors to Maglev America, are in their sixties and seventies.  I myself will be 65 in a couple of months.  We’re a bunch of graybeards!


[1] Wikipedia article on Positive train control (Accessed December 8, 2013)
  http://en.wikipedia.org/wiki/Positive_train_control/   Back to text

[2] Levin, Daniel S., Private communication   Back to text

[3] Wikipedia article on the Metro-North Railroad (Accessed December 8, 2013)
  https://en.wikipedia.org/wiki/Metro-North_Railroad#Signaling_and_Safety_Appliances   Back to text

[4] ibid. (Accessed December 8, 2013)
  https://en.wikipedia.org/wiki/Metro-North_Railroad#Propulsion_Systems   Back to text

[5] Levin, Joshua Zev, LeviCar Website (Accessed December 8, 2013)
  www.LeviCar.com   Back to text

[6] Powell, James and Danby, Gordon, et alia.Maglev America, How Maglev will Transform the World Economy”,  2013
  ISBN-13: 978-1492327592       ISBN-10: 1492327592X
  Library of Congress Control Number: 2013915980       Back to text

[7] U.S. DoT Federal Railroad Admin. High Speed Rail Overview (Accessed December 8, 2013)
  http://www.fra.dot.gov/Page/P0060/   Back to text

[8] California High-Speed Rail Authority (Accessed December 8, 2013)
  http://www.hsr.ca.gov/   Back to text

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