<P> Trevithick was a man of versatile talents, and his activities were not confined to small applications . Trevithick developed his large Cornish boiler with an internal flue from about 1812 . These were also employed when upgrading a number of Watt pumping engines, greatly increasing power and productivity; this led to the highly efficient large Cornish engines that continued to be built right up to the end of the 19th Century . </P> <P> Due to the ever - increasing power demands of the 1800s, especially in manufacturing, innovations were made to existing steam engines and a number of entirely new steam engines were developed . Of these, few brought the high levels of horsepower and efficiency produced by the Corliss engine . Named after its inventor, George Henry Corliss, this stationary steam engine was introduced to the world in 1849 . The engine boasted a number of desired features, including fuel efficiency (lowering cost of fuel by a third or more), low maintenance costs, 30% higher rate of power production, high thermal efficiency, and the ability to operate under light, heavy, or varying loads while maintaining high velocity and constant speed . While the engine was loosely based on existing steam engines keeping the simple piston - flywheel design, the majority of these features were brought about by the engine's unique valves and valve gears . Unlike most engines employed during the era that were using mainly slide - valve gears, Corliss created his own system that used a wrist plate to control a number of different valves . Each cylinder was equipped with four valves, with exhaust and inlet valves at both ends of the cylinder . Through a precisely tuned series of events opening and closing these valves, steam is admitted and released at a precise rate allowing for linear piston motion . This provided the engine's most notable feature, the automatic variable cut - off mechanism . This mechanism is what allowed the engine to function under varying loads without losing efficiency, stalling, or being damaged . Using a series of cam gears, which could adjust valve timing (essentially acting as a throttle), the engine's speed and horsepower was adjusted . This proved extremely useful for most of the engine's applications . In the textile industry, it allowed for production at much higher speeds while lowering the likelihood that threads would break . In metallurgy, the extreme and abrupt variations of load experienced in rolling mills were also countered by the technology . These examples demonstrate that the Corliss engine was able to lead to much higher rates of production, while preventing costly damages to machinery and materials . It was referred to as "the most perfect regulation of speed ." </P> <P> Corliss kept a detailed record of the production, collective horsepower, and sales of his engines up until the patent expired . He did this for a number of reasons, including tracking those who infringed on the patent rights, maintenance and upgrade details, and especially as data used to extend the patent . With this data, a more clear understanding of the engine's influence is provided . By 1869, nearly 1200 engines had been sold, totaling 118,500 horsepower . Another estimated 60,000 horsepower was being utilized by engines that were created by manufacturers infringing on Corliss's patent, bringing the total horsepower to roughly 180,000 . This relatively small number of engines produced 15% of the United States' total 1.2 million horsepower . The mean horsepower for all Corliss engines in 1870 was 100, while the mean for all steam engines (including Corliss engines) was 30 . Some very large engines even allowed for applications as large as 1,400 horsepower . Many were convinced of the Corliss engine's benefits, but adoption was slow due to patent protection . When Corliss was denied a patent extension in 1870, it became a prevalent model for stationary engines in the industrial sector . By the end of the 19th century, the engine was already having a major influence on the manufacturing sector, where it made up only 10% of the sector's engines, but produced 46% of the horsepower . The engine also became a model of efficiency outside of the textile industry as it was used for pumping the waterways of Pawtucket, Rhode Island in 1878 and by playing an essential role in the expansion of the railroad by allowing for very large - scale operations in rolling mills . Many steam engines of the 19th century have been replaced, destroyed, or repurposed, but the longevity of the Corliss engine is apparent today in select distilleries where they are still used as a power source . </P> <P> Water power, the world's preceding supply of power, continued to be an essential power source even during the height of steam engine popularity . The steam engine, however, provided many benefits that couldn't be realized by relying solely on water power, allowing it to quickly become industrialised nations' dominant power source (rising from 5% to 80% of the total power in the US from 1838 - 1860). While many consider the potential for an increase in power generated to be the dominant benefit (with the average horsepower of steam powered mills producing four times the power of water powered mills), others favor the potential for agglomeration . Steam engines made it possible to easily work, produce, market, specialize, viably expand westward without having to worry about the less abundant presence of waterways, and live in communities that weren't geographically isolated in proximity to rivers and streams . Cities and towns were now built around factories where steam engines served as the foundation for the livelihood of many of the citizens . By promoting the agglomeration of individuals, local markets were established and often met with impressive success, cities quickly grew and were eventually urbanized, the quality of living increased as infrastructure was put in place, finer goods could be produced as acquisition of materials became less difficult and expensive, direct local competition led to higher degrees of specialization, and labor and capital were in rich supply . In some counties where the establishments utilized steam power, population growths were even seen to increase . These steam powered towns encouraged growth locally and on the national scale, further validating the economic importance of the steam engine . </P>

Which best describes the relationship between the developments of steam power and the railroad