more abundant fuel. As a result, iron production rose significantly during the last decades of the 18th century. Coal converted to coke fueled higher temperature blast furnaces and produced cast iron in much larger amounts than before, allowing the creation of a range of structures such as The Iron Bridge. Cheap coal meant that industry was no longer constrained by water resources driving the mills, although it continued as a valuable source of power. The steam engine helped drain the mines, so more coal reserves could be accessed, and the output of coal increased. The development of the high-pressure steam engine made locomotives possible, and a transport revolution followed. The steam engine which had existed since the early 18th century, was practically applied to both steamboat and railway transportation. The Liverpool and Manchester Railway, the first purpose-built railway line, opened in 1830, the Rocket locomotive of Robert Stephenson being one of its first working locomotives used. Manufacture of ships' pulley blocks by all-metal machines at the Portsmouth Block Mills in 1803 instigated the age of sustained mass production. Machine tools used by engineers to manufacture parts began in the first decade of the century, notably by Richard Roberts and Joseph Whitworth. The development of interchangeable parts through what is now called the American system of manufacturing began in the firearms industry at the U.S. Federal arsenals in the early 19th century, and became widely used by the end of the century. Second Industrial Revolution (1860s–1914) The 19th century saw astonishing developments in transportation, construction, manufacturing and communication technologies originating in Europe. After a recession at the end of the 1830s and a general slowdown in major inventions, the Second Industrial Revolution was a period of rapid innovation and industrialization that began in the 1860s or around 1870 and lasted until World War I. It included rapid development of chemical, electrical, petroleum, and steel technologies connected with highly structured technology research. Telegraphy developed into a practical technology in the 19th century to help run the railways safely. Along with the development of telegraphy was the patenting of the first telephone. March 1876 marks the date that Alexander Graham Bell officially patented his version of an "electric telegraph". Although Bell is noted with the creation of the telephone, it is still debated about who actually developed the first working model. Building on improvements in vacuum pumps and materials research, incandescent light bulbs