When a number of cables follow the same route, they are generally laid in conduits made up of earthenware or cement ducts; iron pipes are used when the number of cables is small.
The cost of intra-urban railways depends not only on the type of construction, but more especially upon local conditions, such as the nature of the soil, the presence of subsurface structures, like sewers, water and gas mains, electric conduits, &c.; the necessity of permanent underpinning or temporary supporting of house foundations, the cost of acquiring land passed under or over when street lines are not followed, and, in the case of elevated railways, the cost of acquiring easements of light, air and access, which the courts have held are vested in the abutting property.
- New York Rapid Transit railway, showing also the tracks and conduits of the electric surface tramway.
The stones were carefully cleared from the fields, which were also watered from canals and conduits, communicating with the brooks and streams with which the country " was well watered everywhere," and enriched by the application of manures.
Brazil's chief industrial importance is due to its situation in the heart of the "Brazil block" coal (so named because it naturally breaks into almost perfect rectangular blocks) and clay and shale region; among its manufactures are mining machinery and tools, boilers, paving and enamelled building bricks, hollow bricks, tiles, conduits, sewer-pipe and pottery.