Meanwhile multiplied everywhere the attempts to make steam machines able to run on railroads, but always with unsatisfactory results. Among other things it was believed that wheels could not perfectly adhere to the smooth rails, since the steam machine lacked the supporting point provided by the horse hooves sunk in the ground. To overcome these difficulties engineers resorted to the more extravagant devices. John Blenkinsop, director of the mines in Middleton, more practical than anyone, provided besides the wheels a third gear wheel, on which geared the teeth that were placed in the external flanks of the rails. With such system, which prevented the eventual sliding of the wheels on the smooth rails, Blenkinsop managed that his machine towed six cars. However, this system caused frequent stops due to the excessive attrition on the gear wheels. Hence, the problem with adherence on the rails had not been properly solved. It would not be eventually solved until someone had the idea to lubricate the rails and gear wheels with grease.
The locomotive prepared by Blenkinsop to achieve higher adherence on the rails.
The most original and extravagant machine was probably that built by William Brunton, engineer from Derbyshire County, in 1813. He created a kind of mechanical monster with the head represented by the smoking chimney and a cylindrical body from where, apart from the wheels, emerged on the rear part articulated "limbs" which actuating on the rails were aimed to increase adherence. As it is easy to imagine, this attempt was also unsuccessful, due to the overly complex construction and also because of the mechanic who, wanting to increase pressure in the boiler, stiffened in excess the safety valves. The result was that during the trial the boiler exploded, provoking the death of the machinist and injuries to some spectators. Years passed in sterile attempts, but finally someone understood that transport would not possible without a due proportion between the weight of the machine and that of the cars towed by it. This person was the engineer Christopher Blackett.
Indeed, albeit rails seem to be smooth at a first glance, actually they are not, as neither are the rims of the wheels. They are more like an emery surface. This is what allows the wheels to adhere to the rails, allowing the convoy to advance, but there is also an additional advantage: the heavier the machine is, the better is the adherence, because this allows the infinity of grains in the rails and wheels to ingrain even better to each other. Blackett, who in his own mines had replaced long time ago the metallic rails by wooden guides, felt not inclined to the installation of metallic rails with gear teeth, as others had done. As Blackett had decided, the machine should be able to move on normal wheels over normal rails.
Determined to achieve his goal, he talked with William Hedley, manufacturer of steam machines. Blackett firmly believed that the way to go was to determine the relation between the weight of the machine and the heavier load that it could move in the moment of starting the march, and he recommended Hedley to effectuate tests in this regard. Hedley started to experiment and eventually managed to build a perfectly functional machine, baptized as "Puffing Bill". It weighed eight tonnes and could drag a total load of 50 tonnes at a speed of eight kilometers per hour. It was certainly a complete success!
"Puffing Bill", the locomotive built by William Hedley in 1813.
Immediately Blackett ordered three machines of the same type. Some time later, to better distribute the weight of the load over the precarious bottom of the railway, it was increased to eight the number of wheels, coupled by means of gear wheels. When the railways were built with more efficient rails, the number of wheels was reduced to four again. One of these locomotives served until 1862, and since then it was preserved in the Science Museum of London.
George Stephenson
East of the estuary of the river Tyne, near the mining center in Newcastle and precisely in the village Wylam, was born in the spring of the year 1781 George Stephenson. His father, Robert, worked in the mines watching the water pumps, which were indispensable due to the frequent water leaks in the underground galleries. George, like other boys, performed diverse small tasks, such as opening or closing the cancels for the pass of the wagons, or bringing fodder and water for the horses, and he used to spend his spare time in copying the steam machines with clay and wooden pieces. However, among his companions there were some envious ones, and a certain day he found his models turned into a pile of debris. He had ten years then.
Being fifteen years old he was in charge of caring a horse and training it for the works in the galleries, and when he was nineteen he was put in charge of the elevators. The young Stephenson harbored in his inner being the dream of becoming someone some day. The deficiency of the schools and the instruction that was still not compulsory had made of him a poor analphabet, as the immense majority of his contemporaries. Impulsed by the desire of knowledge, he started to frequent nocturnal classes in a nearby town, walking many kilometers every night to attend them. And, since he had will and intelligence, very soon he learnt to read, and the books about physics, chemistry and phylosophy were no longer a secret for him.
Leaving the mine to seek a better future he learnt diverse crafts to earn his livelihood, until he was hired again in another and deeper mine in Killingsworth. Here there was installed a water pump that should have been a jewel of engineering... if it had worked. However, nobody had managed to make it work until then. Stephenson told to a coworker about his potential ability to make it work and the rumor eventually reached the ears of Lord Ravensworth. This one challenged him: if he were successful fixing the machine he would be promoted to foreman, but otherwise he would be fired from his job...