Photo: Amirul Rajiv

The distance between the parallel railway tracks is known as the gauge of the railway. Most commercial railways, except for those running in fairs or exhibitions, are covered by one of the following gauges. These are designated either as Broad Gauge or Standard Gauge or Meter Gauge railways. Mountain Railways are generally of Narrow Gauge. Broad Gauge, which is the widest, measures a distance of 5feet 3inches between the two parallel rails. It was pioneered by the British, and laid in England and it's colonial railways subsequently. The meter gauge measures one meter between the tracks, and was pioneered by the French in Europe. The narrow gauge is usually set at track width of 2 feet.
Curiously however, the Standard Gauge measures 4 feet 81/2 inches or 143.5 centimetre between the parallel railway tracks! Both the dimensions, either in the Imperial or Metric unit of measurement, is a fraction, and not a whole number, which is rather surprising and strange. This railway gauge is widely used by most railways in Europe, North and South America, Africa, Australia and Asia. The exception is the old (British) or geographical India where we have broad, standard, meter as well as narrow gauge of railway which were laid from the 19th century and is co-existing till today!
The history behind this odd distance between the railway lines; called the Standard Gauge, is very interesting. It is rooted in facts that originated from Roman times, long back in history! When the first railway carriages were built, the same tools and set-up was used, which was used for building horse-drawn carriages. But how did the distance between the wheels of the horse-drawn carriage came to be this fraction, i.e: 4ft. 21/2 in. or 143.5 cms? This dimension was based on the width of the ancient roads, dating back to Roman times-- the pioneering age of road building. The Roman roads were built to accommodate the passage of their war chariots, pulled by two horses. The horse, placed side by side, took up a distance of 143.5 centimetre! This dimension later became the distance between the rail tracks for Standard Gauge. It originated in Europe, and later came to America, which preferred the European rather than the British measurements, after becoming independent.
Interestingly enough, it even influenced the building of the American space shuttle at the end of the twentieth century! Initially plans were to have wider fuel tanks for the shuttle. These tanks were to be built in Utah, and had to be transported by railway to the Space Centre at Florida for assembly to the shuttle. It was then realised that the railway tunnels built for Standard Gauge rail tracks, could not transport the desired wide fuel tanks from Utah to Florida! So, in a way the designers of the space shuttle had to compromise their measurement for the width of the fuel tanks based on what the Romans had decided as the ideal width of their roads built for their war chariots!