'Colonial' Gauge

One thing I've been meaning to do since I landed in Japan is to sit down and make a detailed list of all the three foot six inch gauge (3'6") railway systems in the world.

In Britain this gauge used to be called 'Colonial Gauge' because back in Victorian times we used to build in areas that wouldn't have supported the expense of the heavier engineering required for 'standard gauge' track. It's not just a matter of the width of the track itself of course - the real heavier work comes because with standard gauge you can't turn such tight corners and so have to go through or under hills rather than around them.

3'6" gauge networks grew up in south and east Africa, in Australia and New Zealand and of course in Japan where the gauge is now 1071mm. Here's a picture from the Nairobi Railway Museum of an East African Railways Class 30

It's an interesting size because unlike smaller 'narrow gauge' systems it allows the development of heavy and fast locomotives. In fact it's perhaps the most attractive of all railway 'sizes' when you see it at work.

What other countries used this gauge? I'll have to make that list!