The Smallest Layout (2)

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This was my contribution to the World's Smallest Working Model Railroad Challenge of the Micro Layout Website. The goal was, as the title indicates, to build the world's smallest operating model railroad. Conditions have been: a "real" railway with tracks and flanged wheels, and the layout must be able to at least loop trains or switch a car from one track to another.

The volume was the criteria to go. There was a second evaluation: relative smallness, meaning overall length in relation to track gauge.

Conception

After the jury later claimed electric motive power for my first attempt, I asked myself about operations reliability. I had made bad experience with Z gauge. Thus Z, Nm, Nn3 or even smaller gauges look inadequate to me. IMHO the smallest gauge with good reliability is just plain N scale with 9mm gauge.

The car turntable failed already with the first attempt. Since the available turnouts are rather huge it was clear that a layout using turnouts will fail as well. Maybe a loop however? What is the smallest possible radius that a 2-axled loco can run through? I measured the wheels and axles of the loco and determined with CAD how small I can go. With tight curves, even the prototype uses gauge enlargement. Using a gauge enlargement of 0.5mm I've got a radius of 20.5mm! Will it work?

2cm radius plus roadbed makes 6cm in diameter. Since the volume is considerably, layout height was minimized. The minimal scenery consists of just a bit of gravel and herb in the loop center. There are no trees. Even the baseboard is skipped. This makes a overall heigth of just 4mm. Rigidity of the layout comes directly from the rails.

Building the layout

The track plan consists of a circle of 20.5mm radius. Because of the gauge enlargement, no commercial track can be used. Instead I built my first piece of handlaid track: Using CAD I made a jig of the track and printed it out.

About every 30mm, ties from shaped PC board were glued to the paper. The other ties are made from 1.5mm cardboard. The two rails are then bended and soldered to the PCB ties. Two connection wires completed the structure.

Then the 6cm diameter circle was cut out of the paper. Some colors, ballast, a little sand and some woodland turf gave the scenery.

Dimensions are measured with the caliper: 60mm diameter, 4mm height. This makes a volume of 11.3cm3 or 0.69cci - about two third of a cubich inch. The relative smallness is 60:9 respectively 6.667:1. I'm amazed that the second micro layout has got even smaller than the first one!

Operating the layout

Will it work? - Come and see the video:

Video (wmv), 1069kB

Ok - the line is really short. If you have more room ;-) it is a good idea to consider a bigger model railroad. Maybe in a shoe box? There is a huge potential in that mini radius.

Conclusion

However, planning and building of this layout are very much fun, and I have learnt a few new skills. My ultra micro layout therefore shows in a good way that model railroading fun is always possible, even if only small space, time and money are available.

You will find many more good ideas for micro layouts on the Micro Layout Design Gallery.

Appendix 1

Not until completion of the layout I recognized that also other people have built circles of that kind of size. Thus I cannot "patent" it. However I developed my micro layout completely myself. Regarding the height, it is unique.

Appendix 2

(20.12.2008) I won the Worlds Smallest Working Model Railroad Challenge! The layout on the second place - also N scale - is 0.21cm3 or 0.01cci larger :-D

For my very small layout I was awarded with the "very small prize", as Carl Arendt said: I've got a digital caliper. I think this actually a great prize for a modeler!

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