Rail-guided systems seem to be favoured as a solution to urban mass transit.

However, there are limitations. A principal one is that trains have to decelerate to a stop to embark and disembark passengers, then accelerate again. This is inefficient.

When a wheel rolls, the point in contact with the ground (or rail) s actually stationary; the centre (or axle) moves with velocity v, and the "top" with velocity 2v.

If a wheel is very large, this effect can be exploited. Since at any given point the bottom of the wheel is not moving, it is trivially easy to step on or off.

BorgCo engineers are therefore producing a mass transit system based on the Great Panjandrum <link>. Ten metres wide, and fifty metres in diameter, the vehicles run on rails and progress along the tracks at 60 km/h. A raised, paved platform alongside the track allows embarkation and disembarkation. When you get off, you can never be more than 75m from your desired destination (half a rotation).

What could possibly go wrong ?
-- 8th of 7, Dec 04 2019

The Great Panjandrum https://en.wikipedia.org/wiki/Panjandrum
Brilliant, yet sadly flawed. [8th of 7, Dec 04 2019]

Rolling Ferris Wheel Transit Not quite the same. I made mine without a continuous Track. [scad mientist, Dec 08 2019]

//A principal one is that trains have to decelerate to a stop to embark and disembark passengers, then accelerate again. This is inefficient.// - Yes, although the London underground lines mitigate this to some extent by having the tunnels exiting stations run on a downward incline until the midpoint between stations and then upwards to the next station. There is, I suspect, more efficiency to be coaxed from this kind of kinetic-to-potential energy conversion tactic and a sort of full-blown underground roller-coaster is the only logical conclusion.
-- hippo, Dec 04 2019


You should post that; particularly if you can solve the problem of passengers getting on and off without the train actually stopping.
-- 8th of 7, Dec 04 2019


Will the Great Panjandrum transport system be powered with solid-fuelled rocket motors in the same manner as it’s namesake? And will it have the same level of control?

Nice idea though! [+]

Is a variant of Hajile also proposed?
-- Frankx, Dec 10 2019


Possibly; hopefully not; definitely.
-- 8th of 7, Dec 10 2019



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