[totalthrowaway]

This is such a relief to see purely for personal reasons. I was there as a child, and had some memory of 'buses with little wheels on the side' -- and had eventually convinced myself it was a dream. No one I had ever mentioned it to thought it was real.

With adult eyes it seems over-engineered, but I still want to ride it again just because I want to support whoever thought that was a good idea and managed to convince enough people to build it.

[newnewpdro]

> With adult eyes it seems over-engineered

It surprised me to see they didn't simply use retractable railcar wheels like the railroad maintenance trucks, which is apparently a fairly standard "road-rail vehicle":

https://en.wikipedia.org/wiki/Road%E2%80%93rail_vehicle

[Doxin]

Those don't go terribly fast, In addition to the tiny tiny wheels not having a lot of grip leading to slow acceleration and deceleration. Getting those to align with the track is an operation that you'll only want to be doing at standstill.

[newnewpdro]

They aren't the drive wheels so they have no impact on acceleration, the rubber tires are still used for traction.

Alignment could be easily automated today, or a low-tech mechanical guide mechanism could be added for the bus.

I'd expect the maximum comfortable speed to be substantially higher than the guide wheel approach. That guide wheel design seems better suited for aligning the rail wheels than continuous operation.

[tobtoh]

Curious why you feel it's overengineered?

I travelled along the O-bahn for most of my childhood/uni years and I think it's a brilliantly simple system.

Stick a couple of guide wheels on a bus, and you've now got a safe, fast, relatively low cost transport system, that still has the flexibility (once it exits the track) to go where ever it needs to go.

[Doxin]

Is it really over-engineered though? As far as I can tell it's guide wheels welded onto existing busses and some concrete throughs to drive on. It seems to be an exceedingly simple and easy to apply system.