Post by Tom Goodrick on Jul 1, 2010 10:10:06 GMT -5
Trainz 2006 lets you explore the world of MAGLEV Trainz. My last year at NASA was spent looking at MAGLEV technology. I got off on the wrong foot with MAGLEV because my first job was debunking some of the horribly ridiculous claims for MAGLEV as a stage in launching rockets "more cheaply" into space. There was a PH D guy in Washington who was running around convincing everybody the US should invest in MAGLEV launchers. The guy was just trying to make as big a splash as possible to further his career in a far-out technology that even he did not understand very well. I did some research into certain aspects of the technology as well as into some of his claims. It was easy to shoot down down his wild claims. But it was tough work and killed my chances for a lengthy career with NASA. Nobody likes a trouble-maker even when he is right. (If you want more info on this aspect, send me an email.)
But as demonstrated daily in Europe and Japan, MAGLEV trains have some good features. They require the construction of new tracks. These are special "guideways" along which the trains can levitate and travel at up to 350 mph or Mach 0.49 on a cold day. The guideway does not transmit sound either to the train or to the surrounding area because the train does not touch it. Its magnetic levitation causes no sound. There is a pretty good "Whoosh" at max speed and I would expect to see a lot of electromagnetic "noise" that would mess with TV's and computers in houses or offices near the guideway.
Because of the high speeds, the guidway must be elevated to make wide sweeping turns not following any existing railway. Elkevation allows it to pass over settled areas and to avoid interaction with animals and people who might wander near the tracks
The MAGLEV train is lifted magnetically, accelerated magnetically and braked magnetically. The lift and braking can be achieved by use of strong permanent magnets held just above the track when caused to move over aluminum rails, a lift and a drag force is generated. To accelerate the train, segments in the rail are energized to attract elements in the "motor" very much like a standard electric motor works. The lift and drag forces are what I studied and I am a little bothered by what I have heard recently about how the trains work. This is what I studied in detail. The only similarity to aerodynamic forces is in the direction of the force components: Lift is perpendicular to the rail and drag opposes the motion. But the variation of the forces with height above the rail and speed is rather complex and must be solved iteratively in any dynamic assessment. A dynamic assessment is needed because these forces change in weird ways that tend to produce instability.
Recently I saw two things on TV that brought back my interest in this regarding trains. In Huntsville we have this "good ol' boy" TV announcer who does morning shows where he shows off various points of interest in the surrounding area. A new exhibit had gone up in the science museum, primarily for kids but well-attended by all, showing simplified MAGLEV technology. There was a small wooden car with magnets in it that you could push by your hand along an aluminum tracks. As he pushed the car along at a good clip, it wobbled in pitch and quickly slid to a stop when he stopped pushing. That is exactly what the equations I worked with predicted and what I saw in my own trials. You can't get lift without getting drag. The forces are strongly dependent on speed. As you speed up a magnet is lifted up too fast and too much so it falls back down and then the cycle is repeated. The motion of a magnet in the front of a "car" affects the magnetic field for the maget behind it causing an additional variation in its lift and drag.
I was using equations developed by Ford Motor Company engineers in the 1950's when they looked at MAGLEV trains. The obvious conclusion was that you needed to get pretty fancy with electric circuits that would damp the oscillations or you'd make everyone sick and cause such instabilities the trains would crash. Anything you do with stabilization circuits detracts from the electromegnetic efficiency of the operation.
I also saw a piece on The Science Channel (a new HD cable channel I watch frequently) about MAGLEV trains in Europe and Japan where they are in daily operation. (Nobody talks about energy efficiency.) Our NASA engineers concluded you needed a dedicated nuclear power plant for each segment of track. One would be needed for a 5-mile space launch track.
So it was with some interest that I finally took an interest in the MAGLEV feature in Trainz 2006. I decided to make a simple track and test it for train operation. You can make MAGLEV trains up using two types of vehicles - a locomotive and a passenger car. The train is normally made with loco's at each end facing in opposite directions so there is no need to turn the train at the ends of runs. But the traction comes from every car, not just the locos. The locos provide a control station for the engineer.
You make track using a "MAGLEV Guideway" that you stretch along the path and elevate as desired. You can make turnouts using "invisible sections" which appear as dashed sections with left-hand or right-hand turnouts. But these transition sections must be fairly long (500 scale feet) even though they would not be passed at high speed.
I made a track that was about 40 grids long. (Each grid is about 0.43 miles long.) Such a track takes a normal train at 50 mph about 20 minutes from end to end. The test MAGLEV did it in 8 minutes but ran off the end before I could stop it. It looks like it takes about 16 grids to get up to a speed of about 300 mph and about the same to decelerate. I will be placing some kind of structure to show where deceleration must start.
What is the fun in this? Well it makes you think about what MAGLEV trains could do and how to design tracks to suit their operations. I will be giving some thought to the Atlanta-Memphis route that people have talked about (which passes through Huntsville, AL). I envision a non-stop end-to-end train plus a train that would stop in Huntsville. A similar setup would connect Birmingham and Nashville where Huntsville is again at the midpoint.
All the time I worked on MAGLEV, I argued that the train aspect cannot compete with turboprop airliners. I see the airliners as the most efficient way of moving 20-40 people over distances of 100 miles or so. Is that really true?
But as demonstrated daily in Europe and Japan, MAGLEV trains have some good features. They require the construction of new tracks. These are special "guideways" along which the trains can levitate and travel at up to 350 mph or Mach 0.49 on a cold day. The guideway does not transmit sound either to the train or to the surrounding area because the train does not touch it. Its magnetic levitation causes no sound. There is a pretty good "Whoosh" at max speed and I would expect to see a lot of electromagnetic "noise" that would mess with TV's and computers in houses or offices near the guideway.
Because of the high speeds, the guidway must be elevated to make wide sweeping turns not following any existing railway. Elkevation allows it to pass over settled areas and to avoid interaction with animals and people who might wander near the tracks
The MAGLEV train is lifted magnetically, accelerated magnetically and braked magnetically. The lift and braking can be achieved by use of strong permanent magnets held just above the track when caused to move over aluminum rails, a lift and a drag force is generated. To accelerate the train, segments in the rail are energized to attract elements in the "motor" very much like a standard electric motor works. The lift and drag forces are what I studied and I am a little bothered by what I have heard recently about how the trains work. This is what I studied in detail. The only similarity to aerodynamic forces is in the direction of the force components: Lift is perpendicular to the rail and drag opposes the motion. But the variation of the forces with height above the rail and speed is rather complex and must be solved iteratively in any dynamic assessment. A dynamic assessment is needed because these forces change in weird ways that tend to produce instability.
Recently I saw two things on TV that brought back my interest in this regarding trains. In Huntsville we have this "good ol' boy" TV announcer who does morning shows where he shows off various points of interest in the surrounding area. A new exhibit had gone up in the science museum, primarily for kids but well-attended by all, showing simplified MAGLEV technology. There was a small wooden car with magnets in it that you could push by your hand along an aluminum tracks. As he pushed the car along at a good clip, it wobbled in pitch and quickly slid to a stop when he stopped pushing. That is exactly what the equations I worked with predicted and what I saw in my own trials. You can't get lift without getting drag. The forces are strongly dependent on speed. As you speed up a magnet is lifted up too fast and too much so it falls back down and then the cycle is repeated. The motion of a magnet in the front of a "car" affects the magnetic field for the maget behind it causing an additional variation in its lift and drag.
I was using equations developed by Ford Motor Company engineers in the 1950's when they looked at MAGLEV trains. The obvious conclusion was that you needed to get pretty fancy with electric circuits that would damp the oscillations or you'd make everyone sick and cause such instabilities the trains would crash. Anything you do with stabilization circuits detracts from the electromegnetic efficiency of the operation.
I also saw a piece on The Science Channel (a new HD cable channel I watch frequently) about MAGLEV trains in Europe and Japan where they are in daily operation. (Nobody talks about energy efficiency.) Our NASA engineers concluded you needed a dedicated nuclear power plant for each segment of track. One would be needed for a 5-mile space launch track.
So it was with some interest that I finally took an interest in the MAGLEV feature in Trainz 2006. I decided to make a simple track and test it for train operation. You can make MAGLEV trains up using two types of vehicles - a locomotive and a passenger car. The train is normally made with loco's at each end facing in opposite directions so there is no need to turn the train at the ends of runs. But the traction comes from every car, not just the locos. The locos provide a control station for the engineer.
You make track using a "MAGLEV Guideway" that you stretch along the path and elevate as desired. You can make turnouts using "invisible sections" which appear as dashed sections with left-hand or right-hand turnouts. But these transition sections must be fairly long (500 scale feet) even though they would not be passed at high speed.
I made a track that was about 40 grids long. (Each grid is about 0.43 miles long.) Such a track takes a normal train at 50 mph about 20 minutes from end to end. The test MAGLEV did it in 8 minutes but ran off the end before I could stop it. It looks like it takes about 16 grids to get up to a speed of about 300 mph and about the same to decelerate. I will be placing some kind of structure to show where deceleration must start.
What is the fun in this? Well it makes you think about what MAGLEV trains could do and how to design tracks to suit their operations. I will be giving some thought to the Atlanta-Memphis route that people have talked about (which passes through Huntsville, AL). I envision a non-stop end-to-end train plus a train that would stop in Huntsville. A similar setup would connect Birmingham and Nashville where Huntsville is again at the midpoint.
All the time I worked on MAGLEV, I argued that the train aspect cannot compete with turboprop airliners. I see the airliners as the most efficient way of moving 20-40 people over distances of 100 miles or so. Is that really true?