Clever Cornering Contrivances (mini blog)

Real Railway Has Gentle Curves

The above is an aerial view of a bit of the west coast main line (the thin bit on the above map) as it approaches Penrith and where it crosses the M6 (the broader bit). Ironically, the railway is more curved than the motorway.

But when you zoom in, the railway looks almost straight!

Even so, it was necessary to devise a technology that would help the wheels go round corners. This little video explains how clever it is.

Even with the more gentle curves of a fast main line, those wheels shaped like a slice of a cone are necessary to provide a smooth ride and prevent derailments.

Whilst model railway wheels are a good sliced-cone reproduction of the real thing ...

... corners are much, much sharper.

We see the problem with fbb's Greater Manchester liveried Pacer.

Look what happens when you plonk ot on the track. 

Here is a view (plus Mr Tubbles' discarded hair?) from beneath.

The wheels would sit diagonally on the rail and the video showed what would happen! So the clever people at Hornby make one set of wheels pivot ...

... and that's just enough to help it round the corners.

Which brings us to fbb's six wheel coaches. In theory the same applies ...

... but the solution is different. If all three axles were two wheel pony trucks, the carriage would be liable to wobble when trundling along. It needs some stability.

In the Hornby six wheeler ...

... you will find the OO gauge version of a Cartazzi axle on the middle pair of wheels. The wheels slide from side to side in a central tube holding the axle.

Buit on the Hattons Genesis carriage ...

... the wheels, axles and axle boxes are on a subframe, the whole of which slides.

Hattons have even cut a little nibble in the lower step board so the sliding axle box will fit in.

But, of course, if your layout has more gentle curves, they include a step board without a nibble neatly wrapped and in the box as delivered.

Clever eh?

Who would have thought such a simple model in concept would have needed such complex technology. 

Maybe that's why railway modelling is now so very expensive?

These mini blogs are getting longer! More self discipline needed, fbb!

 Next Liepaja blog Friday 18th Oct