Friday, December 12, 2008


Here is a sample switching system that requires no moving track parts. In reality, the track would be pinched between upper and lower wheels, as in the previously posted pencil rendering, but the lower wheels are not shown here. The wheels should be solid and of a hard rubber-like material. Multiple drive wheels overcome the traction deficit inherent in these solid tires.


timote said...

For step 6, what is the support mechanism for the small piece at the bottom of the right wheel? Thinking in three dimensions, I cannot see how to support it - there are wheels underneath and above it, there is no support left or right cause the hanger must be able to go either way, there is no support from where it came cause it didn't exist yet (must taper into existence), there is only a thin strip in one direction...

Dan said...

Dan The Blogger responds-
Great eye. If I had thought about it a bit more, I would have conceived (and drawn it) differently. The short answer is nothing, save that it extends from the same area on the 7th picture, which is connected.
But there are two important points.

1. If the unsupported area didn't exist, the system would still work, assuming that the wheel axles are held square to the cab hangers, the wheel material is solid and fairly hard, like a fork-lift wheel, and the guide wheel has bearings that are of high thrust (sideways) capability, such as the tapered bearings found on the front wheels of cars (which also require high strength against sideways forces) In other words, with the guide wheel engaged, either wheel can be left unsupported.

2. As drawn, the piece in question is thin while the sound deadening material is much thicker. There is nothing that says that the piece you refer to can’t be much thicker, and therefore capable of supporting weight, even when cantilevered for many feet. Is there a limit to how thick this piece could be? Yes. Is there a limit to how far it can extend unsupported? Yes.
Imagine that thin piece of metal as more of a box, thicker. Forget the sound deadening. Frankly, I would redo the sound deadening anyway. Actually I have a drawing in the works of a track system that can make 60 ft. spans. It is a more mature design, yet to be posted.

Remember, I’m putting this stuff out there to be picked over, criticized, second-guessed, and hopefully redesigned completely. You put your finger on what is, for the time being, a disadvantage of hanging pods vs. the Raytheon model. I hope more people weigh in on this. I could very well be missing something completely.

timote said...

Ok, cool - I was thinking that for the design to work as drawn, you'd need to be able to be supported entirely on the outside wheel(s), and that's your concept.

I think it would potentially be a lot of lateral force on the guide, which would become more structural in nature at that point.

Since your overall design implies very cheap (and presumably, therefore plentiful) stations, there will be a lot of forks in the track. Not sure how gradual your concept is for the fork, but I presume it is pretty gradual to prevent slowdowns on the main line and not jerk the cars/customers around. So between plentiful stations and (potentially) long splits, the percentage of time in this mode is potentially fairly high - off the top of my head, maybe as high as 25% between fork out and fork back in. So the wear characteristics of this process is pretty important...

The thicker stock is probably a good idea - maybe allow the wheels to adjust vertically to different thicknesses.