What broad-gauge track width did Brunel's Great Western Railway use?

Brunel’s Great Western Railway used a broad-gauge track width of 7 ft 1/4 in. This unusual gauge was devised by engineer Isambard Kingdom Brunel in the 1830s for the GWR and its associated lines.

The extra width was intended to improve stability, allow larger rolling stock, and support higher speeds and smoother running. Brunel’s gauge became known simply as “broad gauge,” while 4 ft 8 1/2 in became Britain’s standard gauge.

The difference led to Britain’s famous “gauge war.” Passengers and goods sometimes had to change trains where broad- and standard-gauge lines met. Parliament’s 1846 Gauge Act favoured standard gauge, although broad gauge remained important in the GWR’s network for several decades.

The GWR gradually converted its routes, and the last broad-gauge services ran in 1892. The answer is sometimes rounded to 7 ft, but 7 ft 1/4 in is the more precise historical measurement.