One of my recurring dreams is of being on a Ferris Wheel that breaks away from its axle and goes for a little wander in the countryside... with predictably disastrous results.

However, it would be possible to set up a Ferris Wheel to run along a set of train tracks, reasonably easily.

This would necessitate the removal of rail overpass bridges and the heightening of rail tunnels. It would also require careful redesign of bridges, corners and, of course, Ferris Wheels.

To explain, the engine and carriages would be inside the outer (Ferris) wheel, on a pair of massive ring gears, which sit directly upon the rails and are cross-linked to each other at close intervals, with a little play available in hinged joints to allow turning and to cope with uneven heights of the track surfaces.

The engine and the carriages run along the two ring gears, with the engine driving along the inside of the gears on sprocket teeth inside the outer wheels. The engine constantly pulls the inner train up along the inside of the outer wheels, causing them to roll forward on the rails.

Momentum allows the big wheels to run over small bumps and slight grades relatively easily. The size of the wheels would also prevent slipping on wet tracks.

Braking is a matter of slowing the train, so it runs less quickly along the sprockets on the gears.
-- UnaBubba, May 09 2012

Ferris Wheel on a Roll Ferris_20Wheel_20on_20a_20Roll
A not entirely dissimilar idea [hippo, May 09 2012]

This would allow empty carriages to be rotated to the platform as the fuller ones get too crowded. Bun for posting a dream idea.
-- not_only_but_also, May 09 2012


love it! when do tickets go on sale? [+]
-- xandram, May 09 2012


.... or you could just mount a ferris wheel on a train and time its spin to match the speed as though it were rolling and get the same effect

one problem you'd face is precession forces on turns, as the ferris wheel is spinning
-- EdwinBakery, May 09 2012


Even with redesign, I'm not sure how well this would take curves.
-- MechE, May 09 2012


Precession can be overcome by an off-set lateral ballance which throws the weight off kilter just prior to banking and then reverses to snap the flywheel back to vertical at the end of a turn.
-- 2 fries shy of a happy meal, May 09 2012


//One of my recurring dreams...// Yeah, some of the meds'll do that to you.
-- MaxwellBuchanan, May 09 2012


Unless we are proposing track-wheels that are miles in diameter, this would severely limit the length of trains, which is one of their advantages.
-- Alterother, May 09 2012


Love it. +
-- blissmiss, May 09 2012


The tracks would still be usable by normal trains, even long ones, [Alter].
-- UnaBubba, May 09 2012


I don't know that I'd like to be on it when it exceeded 120mph around a curve, [21].
-- UnaBubba, May 10 2012


//I wonder if it might be able to roll faster than normal trains//?

Yes! Just not safely.
-- AusCan531, May 10 2012


We'll give you a helmet, if you think it will help, [AusCan].
-- UnaBubba, May 10 2012


Do the passengers' cabins ride on the giant ring gears, before/behind/above the engine, or do they go around the central axle as in a regular Ferris Wheel?

If the cabins roll on the ring gears, then each cabin is a fixed angle relative to the engine, and a fixed height above the ground -- which is not very Ferris Wheelish... you basically have a dicycle on railroad tracks. A really huge dicycle, but still...

On the other hand, if the cabins' centers don't move relative to the ring gear, the idea is much more interesting (each cabin moves along a cardioid path)... but as hippo pointed out, rather similar to the Ferris Wheel on a Roll idea.

The only way I can see to do something truly novel, and which is sufficiently insufficiently baked for the halfbakery, is to combine and halfway reverse the two options.

Namely, have the engine hanging from (and applying torque to) the Ferris Wheel Train's axis (as in the Ferris Wheel on a Roll), and at the same time, have a pair of ring gears (like in your idea), with a train (or ring?) of passenger cabins rolling along the ring gears, but moving in the opposite direction from the direction which the vehicle is rolling (or perhaps in the same direction, but faster).

Croissants are served in the dining car. [+]
-- goldbb, Jun 13 2012



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