Seeing as I have come into this thread a little late, here goes.
Dwights reply showed what happened with railway guages around the world.
Here is what happened in one country.
Gauges used in Australia
The most used gauges are [1]
* Standard gauge 1,435 mm (4 ft 8 1⁄2 in) 17,678 km - mainly New South Wales and the interstate rail network
* Narrow gauge (aka Cape Gauge) 1,067 mm (3 ft 6 in) 15,160 km - mainly Queensland, Western Australia and Tasmania as well as some of South Australia
* Irish broad gauge 1,600 mm (5 ft 3 in) 4,017 km - mainly Victoria, some South Australia.
While Irish broad gauge was the original standard agreed to amongst the colonies, standard gauge eventually won out, and many sections of broad gauge are slowly being converted to standard gauge.
How's that for confusion.
