Primary industry

This sector of a nation’s economy includes agriculture, forestry, fishing, mining, quarrying, and the extraction of minerals. It may be divided into two categories: genetic industry, including the production of raw materials that may be increased by human intervention in the production process; and extractive industry, including the production of exhaustible raw materials that cannot be augmented through cultivation.

The genetic industries include agriculture, forestry, and livestock management and fishing—all of which are subject to scientific and technological improvement of renewable resources. The extractive industries include the mining of mineral ores, the quarrying of stone, and the extraction of mineral fuels.

Primary industry tends to dominate the economies of undeveloped and developing nations, but as secondary and tertiary industries are developed, its share of the economic output tends to decrease.

Secondary industry

This sector, also called manufacturing industry, (1) takes the raw materials supplied by primary industries and processes them into consumer goods, or (2) further processes goods that other secondary industries have transformed into products, or (3) builds capital goods used to manufacture consumer and nonconsumer goods. Secondary industry also includes energy-producing industries (e.g., hydroelectric industries) as well as the construction industry.

Secondary industry may be divided into heavy, or large-scale, and light, or small-scale, industry. Large-scale industry generally requires heavy capital investment in plants and machinery, serves a large and diverse market including other manufacturing industries, has a complex industrial organization and frequently a skilled specialized labour force, and generates a large volume of output. Examples would include petroleum refining, steel and iron manufacturing (see metalwork), motor vehicle and heavy machinery manufacture, cement production, nonferrous metal refining, meat-packing, and hydroelectric power generation.

Tertiary industry

This broad sector, also called the service industry, includes industries that, while producing no tangible goods, provide services or intangible gains or generate wealth. This sector generally includes both private and government enterprises.

The industries of this sector include, among others, banking, finance, insurance, investment, and real estate services; wholesale, retail, and resale trade; transportation; professional, consulting, legal, and personal services; tourism, hotels, restaurants, and entertainment; repair and maintenance services; and health, social welfare, administrative, police, security, and defense services.

Quaternary industry

An extension of tertiary industry that is often recognized as its own sector, quaternary industry, is concerned with information-based or knowledge-oriented products and services. Like the tertiary sector, it comprises a mixture of private and government endeavours. Industries and activities in this sector include information systems and information technology (IT); research and development, including technological development and scientific research; financial and strategic analysis and consulting; media and communications technologies and services; and education, including teaching and educational technologies and services.

In 1916 the Nickel Plate became part of the railroad empire of the Van Sweringen brothers. They were the developers of the Cleveland suburb of Shaker Heights, and they needed a transit line to the city. As president they appointed John J. Bernet, who made the Nickel Plate a profitable line, rehabilitating and modernizing it. They added several other lines until the railroad had over 1,700 miles (2,700 km) of operating track between Buffalo, N.Y.; Wheeling, W.Va.; Chicago; and St. Louis, Mo. In 1964 the line was merged with the Norfolk and Western, giving the N&W a rail network extending from the Atlantic to the Great Lakes.