The Great Western Railway (GWR), the most advanced in the world, was called ‘God’s wonderful railway’.

Canals brought progress in the 18th century, but in the 19th it was the strength of steam and the development of the railways that made Britain the world’s powerhouse.

And the best railway was the GWR which ran from London to Bristol, crossing river valleys and tunnelling miles through chalk downland.

The GWR was the crowning achievement of its youthful engineer-in-chief, Isambard Kingdom Brunel. He used a wider track than other railways, for speed and passenger comfort. He was right, but eventually the GWR had to standardise on a narrower gauge.

Brunel was only 26 when he was put in charge of this immense project and his assistant, Daniel Gooch, was just 21. Together they pioneered a rail network that would eventually run for 4,800km (3000 miles), from London to the Cornish Riviera, north to the Midlands and south to the Dorset coast.