Editing Track gauge (section)

===Gauge differences===
The Liverpool and Manchester was quickly followed by other trunk railways, with the [[Grand Junction Railway]] and the [[London and Birmingham Railway]] forming a huge preponderance of [[standard gauge]]. When Bristol promoters planned a line from London, they employed the innovative engineer [[Isambard Kingdom Brunel]]. He decided on a wider gauge, to give greater stability, and the [[Great Western Railway]] adopted a gauge of {{Track gauge|7ft}}, later eased to {{Track gauge|7ft0.25in|lk=on}}. This became known as ''[[broad gauge]]''. The [[Great Western Railway]] (GWR) was successful and was greatly expanded, directly and through friendly associated companies, widening the scope of broad gauge.

At the same time, other parts of Britain built railways to standard gauge, and British technology was exported to European countries and parts of North America, also using standard gauge. Britain polarised into two areas: those that used [[Brunel gauge|broad gauge]] and those that used standard gauge. In this context, standard gauge was referred to as "narrow gauge" to indicate the contrast. Some smaller concerns selected other non-standard gauges: the [[Eastern Counties Railway]] adopted {{Track gauge|5ft|lk=on}}. Most of them converted to standard gauge at an early date, but the GWR's broad gauge continued to grow.

The larger railway companies wished to expand geographically, and large areas were considered to be under their control. When a new independent line was proposed to open up an unconnected area, the gauge was crucial in determining the allegiance that the line would adopt: if it was broad gauge, it must be friendly to the Great Western railway; if narrow (standard) gauge, it must favour the other companies. The battle to persuade or coerce that choice became very intense, and became referred to as the [[British Gauge War|"gauge wars"]].

As passenger and freight transport between the two areas became increasingly important, the difficulty of moving from one gauge to the other—the ''[[break-of-gauge]]''—became more prominent and more objectionable. In 1845 a [[Royal Commission on Railway Gauges]] was created to look into the growing problem, and this led to the [[Regulating the Gauge of Railways Act 1846]],<ref>{{cite web
| url = http://www.railwaysarchive.co.uk/documents/HMG_Act_Reg1846.pdf
| title =An Act for regulating the Gauge of Railways
|date = 18 October 1846
|access-date =26 April 2010}}</ref> which forbade the construction of broad gauge lines unconnected with the broad gauge network. The broad gauge network was eventually converted—a progressive process completed in 1892, called [[Track gauge conversion|gauge conversion]]. The same Act mandated the gauge of {{Track gauge|5ft3in|lk=on}} for use in Ireland.