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Standard Railway Gauges

by Jim Nelhams

An article in the HADAS Newsletter, May 2003, tells us that very old wheel tracks in Malta are a “standard” width apart, and that the distance is close to the Standard Railway Gauge. Should this be a surprise?

A number of mostly humorous articles have been written on the subject, but they do seem to contain an element of possibility. I’ll try to summarise.

Firstly, the standard railway gauge throughout most of the world is 4 foot 8.5 inches. There are exceptions – Spain, Portugal, Ireland and most of Eastern Europe have different gauges, and there are a number of narrow-gauge railways throughout the UK.

Most early major roads in Europe were built by the Romans particularly to help them transport the army and the supplies that it needed. They would have used horse drawn carts, and chariots. Some of the equipment required, such as the yoke worn by the horses, as well as the carts and chariots, would have used standard specifications and models which were designed for practical purposes. A yoke for two horses would need to be comfortable for them, and would also need to fit between the shafts of the vehicle. This would also allow the wheels to run without the dirt kicked by the horses getting underneath them. So our starting point is the width of two horses!

Once this has been established and the wheels start to travel on the road, ruts will appear, and any vehicle that does not conform to these ruts is liable to be damaged. Visitors to Pompeii will have seen ruts in the stone roads and will also have seen the stepping stones in the roads. The stones allowed pedestrians to cross the road without stepping in the “pollution”, but they would have caused a major problem had not all the wheeled traffic been wide enough to span them. So perhaps the ruts are actually grooves cut to guide the wheels rather than grooves made by the wheels themselves. And of course, the stepping stones would have the effect of keeping the traffic to a sensible speed. So did Pompeii effectively have a tramway and speed bumps? Also, since there are no passing places, did the streets operate a one way system?

The tramway idea is not as absurd as it sounds. Evidence exists that the Persians and Assyrians, to improve the safety of their war chariots, deliberately cut grooves on mountain passes to prevent the wheels from slipping sideways. The distance between these grooves fits closely to our standard.

Move on to the industrial revolution. The first railways would have been horse drawn, with the trucks adapted by those already skilled in carriage building. So why change the width? After all, it did allow for the horses to walk between the rails without risk of injury from them.

How was the standard spread? Well if you want to join two railways together, or even build one railway in sections that join up later, you must have a standard. And when steam power comes along, the cost of changing to anything else may be prohibitive. Isambard Kingdom Brunel built his Great Western Railway with a seven foot gauge, and it was undoubtedly faster, smoother and more economic, but being a minority of one, the great man was unable to persuade Parliament that his answer was “best”, and was forced to conform.

During the Victorian era, railways sprang up all over the world, most of them were built by British engineers, and started with British locomotives and other equipment. So they used the same gauge.

Effectively, the standard had become a default, and had perpetuated that used long before railways came along.

Some isolated places used different gauges. Even today, most of Eastern Europe has rails wider apart, and trains travelling between west and east have to stop and change wheels.

And the effect of the standard must not be underestimated. How does equipment reach Cape Canaveral? And how are the rockets moved to the launch pads? You’ve got it – by rail. So perhaps the size of the rockets is influenced by the width of those long dead horses.

It’s not finished. The love of some of our road engineers for speed bumps and width restrictions could have similar effects. Cars should be narrow enough to go through the width restrictions but with wheels far enough apart to miss the bumps! Pity the poor person driving a Robin Reliant! Except that speed bumps don’t seem to have a standard width, so there have been lots of complaints from the Ambulance services.

And with tramways returning to our cities, we do not want our car wheels to catch in them. (Remember the film Genevieve!). So cars must use a different standard, if that makes sense.

I leave you to make up your own mind, but it does seem to be a case of the old adage, “if it works, don’t change it!”

So why did Brunel consider a 7 foot gauge? Well, I don’t know the answer, but the standard width of canal locks in this country is either 7 foot or 14 foot -----