Does size matter?

By Daniel Pyke

IF you look back at the railway 100 years ago, even 200 years ago looking back at the earliest railways, you'd see something still recognisable at it's heart - the rails.

Over this time rails have evolved their shape with flat bottomed "Vignoles" rail being the most common in use today - but other special shapes being used still too.

The biggest evolution (aside from the metallurgy and quality which is difficult to see), is the rail length. The first railways used rails less than 2 metres in length, whereas todays railways may use 120 metre long rails. Why?

Is bigger really better?

Why have rail lengths increased by so much? There are many reasons, but I’ll explore a few in this article.

Joining rails reliably is not easy. Now before I get various suppliers jumping in with "our failure rate is 10 times lower than competitor products" etc, I'll point out that every joining method has a failure rate and, (so far at least), those failure rates are much higher than the parent, (unjoined), rail. So every time you add a joint of any type (weld, fishplate etc), you introduce an increased risk of failure at that point. It stands to reason you want to avoid adding potential problem points into your network where practical.

If we take a look at the number of joints needed to make a single kilometre of track, you’ll see just what a huge effect on the number of joints needed the rail length has.

So given a choice using longer rails seems a smarter choice to reduce risk/failure rates. So far my article has mostly been theoretical - does the data back this up? The data below is a few years old now but is an amalgamation of rail failure statistics from both the UK and France so hopefully representative of European practices where long length rails are already routinely used.

Over one third of the broken rails are from