|
Mt. Lebanon Tunnel
The Mt. Lebanon Tunnel is a light rail tunnel in Allegheny County, Pennsylvania, also known as the Dormont/Mt. Lebanon Transit Tunnel, part of the Pittsburgh Light Rail system. The long tunnel connects the and stations beneath Washington Road & West Liberty Ave. from Shady Drive East to McFarland Road at a maximum depth of , and runs beneath a cemetery. The pre-tunnel trolley street line, which ended in 1984, ran from the long-removed Clearview Loop stop on Alfred St. (Mt. Lebanon) to the intersection of McFarland Rd. and Raleigh Ave. (Dormont). The tunnel was constructed by a technique called the New Austrian Tunnelling method, a tunneling process developed in the early 1960s that has become the primary tunneling practice in Europe. This is the first time that this money-saving technique was used for transit construction in the United States. The difference with NATM lies in the means of support required to maintain the rock cavity and the configuration of the tunnel struc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pittsburgh Light Rail
The Pittsburgh Light Rail (commonly known as The T) is a light rail system in Pittsburgh, Pennsylvania, and surrounding suburbs. It operates as a deep-level subway in Downtown Pittsburgh, but runs mostly at-grade in the suburbs south of the city. The system is largely linear in a north-south direction, with one terminus just north of Pittsburgh's central business district and two termini in the South Hills. The system is owned and operated by Pittsburgh Regional Transit. It is the successor system to the streetcar network formerly operated by Pittsburgh Railways, the oldest portions of which date to 1903. The Pittsburgh light rail lines are vestigial from the city's streetcar days, and is one of only three light rail systems in the United States that continues to use the Pennsylvania Trolley (broad) gauge rail on its lines instead of . Pittsburgh is one of the few North American cities that have continued to operate light rail systems in an uninterrupted evolution from the fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Port Authority Of Allegheny County
Pittsburgh Regional Transit (PRT, formerly Port Authority of Allegheny County) is the second-largest public transit agency in Pennsylvania and the 20th-largest in the United States. The state-funded agency is based in Pittsburgh and is overseen by a CEO and a nine-member board of unpaid volunteer directors, five of whom are appointed by the county executive and approved by the county council; and one each by the majority and minority leaders by each political party. After operating as the Port Authority of Allegheny County for most of its history, the agency rebranded under its current name in June 2022. In , the system had a ridership of . Pittsburgh Regional Transit's bus, light rail and funicular system covers Allegheny County. On some longer-distance routes, service extends into neighboring counties such as Beaver, Washington, and Westmoreland. These counties have their own transit systems, including several routes that run into downtown Pittsburgh, where riders can make ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Austrian Tunnelling Method
The New Austrian tunneling method (NATM), also known as the sequential excavation method (SEM) or sprayed concrete lining method (SCL), is a method of modern tunnel design and construction employing sophisticated monitoring to optimize various wall reinforcement techniques based on the type of rock encountered as tunneling progresses. This technique first gained attention in the 1960s based on the work of Ladislaus von Rabcewicz, Leopold Müller, and Franz Pacher between 1957 and 1965 in Austria. The name NATM was intended to distinguish it from earlier methods, with its economic advantage of employing inherent geological strength available in the surrounding rock mass to stabilize the tunnel wherever possible rather than reinforcing the entire tunnel. NATM/SEM is generally thought to have helped revolutionise the modern tunneling industry. Many modern tunnels have used this excavation technique. The works built by the Sequential Excavation Method are very attractive from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overhead Catenary
An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, trolleybuses or trams. It is known variously as: * Overhead catenary * Overhead contact system (OCS) * Overhead equipment (OHE) * Overhead line equipment (OLE or OHLE) * Overhead lines (OHL) * Overhead wiring (OHW) * Traction wire * Trolley wire This article follows the International Union of Railways in using the generic term ''overhead line''. An overhead line consists of one or more wires (or rails, particularly in tunnels) situated over rail tracks, raised to a high electrical potential by connection to feeder stations at regular intervals. The feeder stations are usually fed from a high-voltage electrical grid. Overview Electric trains that collect their current from overhead lines use a device such as a pantograph, bow collector or trolley pole. It presses against the underside of the lowest overhead wire, the contact wire. Current collectors are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allegheny County, Pennsylvania
Allegheny County () is a county in the Commonwealth of Pennsylvania. It is located in Southwestern Pennsylvania. As of the 2020 census, the population was 1,250,578, making it the state's second-most populous county, following Philadelphia County. The county seat is Pittsburgh. Allegheny County is included in the Pittsburgh, PA Metropolitan Statistical Area, and in the Pittsburgh Designated Market Area. Allegheny was the first county in Pennsylvania to be given a Native American name. It was named after the Lenape word for the Allegheny River. The meaning of "Allegheny" is uncertain. It is usually said to mean "fine river". Stewart says that the name may come from a Lenape account of an ancient mythical tribe called ''"Allegewi"'', who lived along the river before being taken over by the Lenape. History Prior to European contact, this area was settled for thousands of years by succeeding cultures of indigenous peoples. During the colonial era, historic native groups kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shotcrete
Shotcrete, gunite (), or sprayed concrete is concrete or mortar conveyed through a hose and pneumatically projected at high velocity onto a surface, as a construction technique, first used in 1907 invented by Carl Akeley. It is typically reinforced by conventional steel rods, steel mesh, or fibers. Shotcrete is usually an all-inclusive term for both the wet-mix and dry-mix versions invented by Akeley. In pool construction, however, ''shotcrete'' refers to wet mix and ''gunite'' to dry mix. In this context, these terms are not interchangeable. Shotcrete is placed and compacted/consolidated at the same time, due to the force with which it is ejected from the nozzle. It can be sprayed onto any type or shape of surface, including vertical or overhead areas. Shotcrete has the characteristics of high compressive strength, good durability, water tightness and frost resistance. History Shotcrete, then known as gunite, was invented in 1907 by American taxidermist Carl Akeley to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CCTV
Closed-circuit television (CCTV), also known as video surveillance, is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted, though it may employ point-to-point (P2P), point-to-multipoint (P2MP), or mesh wired or wireless links. Even though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that require additional security or ongoing monitoring (Videotelephony is seldom called "CCTV"). Surveillance of the public using CCTV is common in many areas around the world. In recent years, the use of body worn video cameras has been introduced as a new form of surveillance, often used in law enforcement, with cameras located on a police officer's chest or head. Video surveillance has generated significant debate about balancing its use with individuals' right to privacy even when in public. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnels In Allegheny County, Pennsylvania
A tunnel is an underground passageway, dug through surrounding soil, earth or rock, and enclosed except for the entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, or people. Special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. Tunne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Overhead Catenary")
