A reference to this traction technology just came up recently where the gentleman was searching for a method(s) to increase the pulling power of his 2-6-6-2 Spectrum steam engines.
There was a link to a video, and subsequently found a number of other videos touting the significant improvements available. But as I inspected the videos I found almost all of them dated about 5 years ago. And I could find NO mention of experiments on American model steam engines?
It seems to me that the fundamental idea is based on the idea that great increase in model adhesion will follow the application of magnetic-field attraction in place of weight. The idea is to put some of those powerful NIB-type magnets on the ‘bottom’ of existing locomotives, and then line the track with relatively large and heavy steel or at least ferromagnetically-susceptable plates. The magnets attract the plates and voila! more adhesive force on the driver treads (they also mention better electrical contact, perhaps in part via pickups on ‘sprung drivers’ as the chassis pulls down on the suspension) for a comparatively small magnet size.
We can see almost immediately what a ridiculous alternative to ‘more weight’ this approach will be. The magnetic attraction will follow a square law, with increasingly dramatic “adhesion” for comparatively small variance of the distance between the magnets and the active part of the underlying plate. I’d expect even the small variations unavoidable in laying plates relative to railhead of the actual track would cause either loss of effective adhesion or waaaaay too much adhesion resulting in runaway attraction and virtually ‘nailing’ the locomotive to the track.
In short, a British idea comparable to the actual sensibility of the original Webb compound or Dean’s “wheelbaseless” locomotive as described in Fryer. I’m tempted to think of it as the Lucas implementation of Magnetraction, although of course the two approaches are quite different.
Personally I don’t see a way to make it even borderline practical without almost inhuman attention to lining and surfacing both the trackwork and the underlying plates… perhaps not even then. Perhaps someone else who reads this will see how.
The German manufacturer Busch makes a HO scale light railway running on 6.5mm (Z scale) track. The diminuitive locos weigh next to nothing and would hardly pull their weight without the help of a little magnet stuck underneath the engine. The track has a metal strip incorporated. Works quite nicely.
They’re smart enough to keep the magnetic assistance relatively light, and to incorporate the (thin) magnetic strip into what is essentially snap track.
How does the system perform on field grades, pulling a load?
If you would have spent some time: a) watching the video or b) read the instructions on the website, you would have known that the thin(!) metal plates are easy to install, and if you get various heights on the install, how is the rest of your trackwork looking?
That’s bordering on slander to accuse the British of being bad engineers.
I see no problems whatsoever with the product. I know that it is going to help many lightweight small engines on inclines.
One of their videos does show a ‘retrofit’,…troublesome but doable.
I’m thinking it may not be necessary to equip all ones’s locos?
And only on the most troublesome grades.
I wasn’t too enamored with their method/device for attaching the magnets to the locos.
I’ve forgotten most of my ‘magnet science’, but I wonder it those plates could be replace by 1-2 good metal rods buried in the roadbed??,…maybe even energized ones??
Seems to me I recall that stainless is not as good a magnet material??
I was being playful and not particularly serious. But you cannot really argue that either Webb’s approach to LP valve gear or the other constituted a wizard approach to design, any more than you can excuse the issues with middle big-ends in A4s.
Remember that part of this discussion is why there is relatively little adoption with larger prototypes, including presumably American engines up to articulated size.
You can get around at least some of the problem by increasing the area of the magnetic-field interaction, with the ‘best’ way probably being to use either a relatively large number of ‘weaker’ magnets or some kind of Halbach-array equivalent that gives a consistent field ‘normal’ to the space between the plates. Hopefully the proponents of the system will think about this.
“Energizing” a rod isn’t going to help you much; I’m presuming you mean with the rods vertical and wound with solenoid coils as electromagnets. There have been real-world experiments with this, and they do work … but only with servo control of the magnetic field which effectively limits the ‘peak’ adhesion over the rod to a comparatively small fraction of the achievable magnet power. I suspect you’d be better off with a geometry closer to a ‘plate’ that matches field lines with a distributed array of permanent magnets on the locomotive baseplate, using the same progressive actuation of sequential magnets that was used for the intermittent stud contact system GE developed for streetcars, or for high-speed rail. That is more complicated technically, I think, than something using the same proportional control on a moving plate.
The real issue here, which may turn out to be a non-issue in practice, is only that the type of magnet and expected field attraction may be ‘too great’ to give what we expect as meaningful levels of additional adhesion for the cost and work done to provide it, if smooth operation or assistance in ‘unattended places’ is the goal (I am thinking of sharp helixes as one place in particular where effective magnetic assistance would be highly valuable).
The logical solution, as at least two people have noted recently, is to settle for less magnetic strength to gain the necessary smoothness. Stainless might ‘get you there’ a bit better with excessively powerful magnets … but the right answer, as Graffen indicated, is to use thinner plates of good material, and more distributed permag field lines, instead.
One of the great advantages to their design is that, with a little care, there should be little secondary problem from having a magnet or array glued to the underside (as opposed to fixed magnet location in the track) and the adhesion enhancement comes only when there are plates under the track (which can of course be varying thickness, or even ‘coarsely’ adjustable via moving plates in and out of the interaction field in servo). So you maintain interoperability even when you don’t want the ‘magnetraction’, something much less easy to do with magnetizing the wheels relative to the railheads.
I was informed on another possible bonus of this system:
When using sound decoders with DDE, you can get real strained sound on the inclines as the magnets increase the motors load reading while you get no effect on curves.
What it leads me to wonder about as a ‘follow-up’ is whether some device that increases the subgrade ‘susceptibility’ actively could be used to control precisely what the degree of increased load reading is at particular points on the grade, or for a programmed ‘consist weight’ that doesn’t reflect the actual mass or resistance of the consist… now, among other things, that might be done or at least ‘fine-tuned’ with some track electromagnets… this is getting more interesting by the post.
I was one of the early respondents to this (or the other?) thread. Where did it go? The OP has a habit of linking to other forums, perhaps a moderator excised the thread and the OP began this new one?
Ed, I did NOT link to another forum,…only said ‘on another subject thread’.
I really have trouble with this ‘isolationist stance’ that doesn’t seek to fully explore the world.
Actually I was not suggesting vertical rods, nor wound coils, etc…too complicated.
What I had in mind was impoving the magnetic properties of the rods in leiu of plates by imparting better magnetic characterists to these base fixtures when manufacturing them…And then these rod(s) might be easier to install under the tracks??
I think I remember that we very often create magnetism in certain materials,…so can we vary this amount we give it?