Newly laid track
520 metres of new track at Llangennech

The battle to establish a standard gauge between the rails across Britain ended 129 years ago.

So why do we still have variations in track today?

The end of the line for Brunel’s broad gauge

Paddington to Penzance, the weekend of 20 to 23 May, 1892. Railway workers rip up the last stretch of Isambard Kingdom Brunel’s broad gauge track. They convert 213 track miles to the standard gauge for the South Wales Railway, closing one of the railway’s most divisive and controversial chapters.

Pioneering engineers Brunel and George Stephenson had been at war over their attempts to each establish a standard distance between the rails on Britain’s railway.

Old photograph of Isambard Kingdom Brunel with top hat and cigar
Isambard Kingdom Brunel

A standard would create a national network of railway lines and enable trains to run uninterrupted by changes in the infrastructure for the first time.

Brunel believed his 7ft 1/4 in broad gauge rail would mean faster and smoother journeys, proven by its success on the his Great Western Railway linking Paddingon with South West England.

George Stephenson favoured 4ft 8 1/2 in between the rails, based on the needs of the horses and carts for which the early railways had been built.

Archive drawing of the broad gauge
Drawing of Brunel's broad gauge from our archive

A new gauge for new technology

Archive drawing of the standard gauge
An archive drawing of the standard gauge

John Page, a records controller at our archive, describes Brunel as a radical: “The Stephenson gauge came from George’s experience of the colliery railways of the early 1800s, and maintained the horse-and-cart gauge.

“Brunel was the one to suggest a new gauge for a new technology – to leave the horse and cart behind and have a bespoke gauge for bespoke locomotives. He believed that his gauge would lead to faster and smoother journeys.

“Passenger experience was good on the broad gauge. The problems came when the broad gauge met the standard gauge, as passengers would need to swap trains to continue their journeys.”

The conflict was personal as well as professional; Brunel found himself against his close friend Robert Stephenson, who took his father George's side.

Despite Brunel's firm belief that a wider track was the superior design, Stephenson’s gauge was built on most of the railway in the coming decades and the broad gauge ultimately lost.

Railway companies laid no more broad gauge track after about 1860, according to ‘The Oxford Companion to British Railway History’, and existing track was converted to standard gauge, “achieving the recommendation of the Gauge Commissioners without compensation”.

John said: “I do not think there is any coincidence to the fact that once Brunel died (1859), so did the future of the broad gauge.

“It is a testament to the power and influence of Brunel and his unerring vision, that broad gauge existed, and continued expanding until his death. When you consider that the broad gauge extended to only 544 track miles and was restricted by the Railway Regulation (Gauge) Act 1846, it was never going to surpass or trump the Stephenson gauge.”

Brian Whitney, an engineering expert specialising in track at Network Rail, said: “Was it the right thing? I don’t think I know. It was that the majority rules, almost, in the mid-1800s.”

Archive drawing of the mixed gauge
An archive drawing of the mixed gauge – an adaptation of the remaining broad gauge railway before it was fully converted to the country-wide standard

The legacy of our Victorian railway revolution

But the end of the end of the broad gauge did not mean an entirely standard railway. In fact, we continue to deal with our predecessors’ variations in track design today.

However, there was more standardisation in the decades following the formation of British Railways in 1948, which brought the railway under one operator.

Brian said: “From about 1970 onwards, we’ve been fairly standard, using just three [types] of rail. You need to be a bit careful – there’s not just one type of rail everywhere.”

Close up of older-style bullhead rail, fastened to a 'chair' on the sleeper
The older-style bullhead rail, fastened to a ‘chair' on the sleeper

Differences in rail can make it more challenging and time consuming for us to replace a section of rail when it breaks or becomes too worn for trains to run safely.

In some parts of the railway, switches and crossings (moveable sections of track that guide trains from one track to another and allow them to cross paths) have been built with bespoke rail or specifically designed cast crossings.

This is rail specifically designed and manufactured for that precise location. We must make a new one; it’s not possible to replace it with an off-the-shelf piece.

Elsewhere, we have bullhead rail, which must be replaced with bullhead rail; our more common flat bottom rail is incompatible with it.

Furthermore, when we install a new rail beside a worn rail, we get a difference in profile that we need to blend in during the welding process. We tend to get a bigger difference on curves, where rails wear more significantly, than on straight pieces of track.

Today we have three types of rail across Britain …

Bullhead rail

This dates from Victorian times and was named after the shape of the end of the rail (thick at the top and bottom, and thin in the middle).

It’s the least common of our rail and is typically found on tertiary lines or quieter secondary railway routes than on busier Main Lines, which we need to renew more frequently. It’s also still found on the London Underground.

Drawing of bullhead rail compared with flat bottom rail
Bullhead rail (left) and flat bottom rail (right)

Brian said: “The lower speed, lower tonnage, less critical bits of railway will get maintained for much longer without renewals. It’s not cost effective to renew something that’s carrying very little traffic at a lower speed.”

Bullhead rail must be replaced with bullhead rail because it’s designed to attach to a special base plate known as a chair that sits on top of the sleeper.

Flat bottom rail (in two sizes)

Close-up of flat bottom rail
The modern-style flat bottom rail, fastened directly to the sleeper (no ‘chair' required)

Flat bottom rail was developed as a replacement for bullhead rail.

This dates from the 1950s and is used on most of our railway today. Just as it sounds, it has a very wide, flat bottom. This larger rail is an improvement on older rail designs; it means stronger track that lasts longer.

It comes in two sizes – 56kg and 60kg, which we’ve used since 2000.

Brian said: “Generally the trend has been to increase the size to increase the stiffness of the rail and the ability to support higher loads … What would have been perfectly adequate 100 years ago for fewer trains at 60 miles an hour is not serviceable or economic for a larger number of trains at 125 miles per hour.”

What really makes it distinct from bullhead rail is shape and that we don’t generally need to attach it to a specific base plate on the sleeper. Instead, we can fasten it directly onto the sleeper.

Read more:

Looking after the railway – track

Eminent engineers

The Network Rail archive

Our history