Because they run on rails, railroads need steel, and because it is rather heavy, steel needs railroads. Secondly, there were wages. Britain, and to a lesser extent the Low Countries, had the highest wages in the world at the beginning of the 18th century. In 1725, wages in London were the equivalent of 11 grams of silver per day. In Amsterdam, they were 9 grams. In Beijing, Venice, and Florence, they were under 4. And in Delhi, they were under 2.