It will be generally conceded that there are three major preconditions for the successful launch of any modern industry: it needs to have identified an assured market of consumers which can be expected to expand over the years; it has to be able to call on a reliable workforce available for employment; and thirdly, it needs to have access to a body of primary producers. The railway industry, which in France entered its period of rapid expansion in the 1840s, provides as good an instance as any of an enterprise embracing from the start these three essential prerequisites for success. The market here consisted of a potentially large number of customers looking for a more rapid, easier and cheaper means of undertaking long journeys which had previously necessitated travel by horse-drawn coach, river barge or coastal vessel; together with a smaller but equally important group of entrepreneurs able to profit from the fast transport of heavy goods in bulk. The workforce originally consisted of the armies of labourers needed to make the cuttings, bore the tunnels, build the viaducts and lay the tracks; and later, of the more highly trained body of engine-drivers, stokers, signalmen, stationmasters etc. required for the running of the trains. The primary producers, the third essential requirement, were already present in the men who sank the mines and dug the coal which, before the coming of electric power, was the only available fuel for locomotion.

The same tripod of necessary preconditions was present to support the nascent theatre industry at about the same period.