Although the concept of the steam engine had been experimented with for hundreds of years, it made its most significant impact during the 18th century. Scottish inventor, James Watt, improved upon the technology which had been developed by his predecessors, creating the efficient design which was fundamental to the Industrial Revolution. These engines led to the introduction of the steam locomotive to the railways of 19th century Great Britain, used for the transportation of both passengers and goods. Toy manufacturers took advantage of the excitement surrounding this revolutionary technology, producing miniature, simplified versions for children from the late 1800s onwards. For adult steam enthusiasts, more complex model steam trains were available. Kits were - and still are - also manufactured, from which fans could build their own model. Fully assembled antique and vintage models are popular on the collectors' market, with rare versions having sold for tens of thousands at auction in the past.