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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <title>Guidelines for Managing Suspected Chemical and Biological Agent Incidents in Rail Tunnel Systems</title>
      <link>https://trid.trb.org/View/1540944</link>
      <description><![CDATA[These emergency management guidelines are designed to help transit managers (1) prepare and implement standard operating procedures (SOPs) for handling potential and actual chemical or biological agent attacks in their rail tunnel system and (2) understand the rationale for the recommended emergency actions. This document can also serve as a background reference guide for the emergency manager to use in developing SOPs, which should incorporate the recommendations presented in this document, together with site-specific operational methods used in the rail tunnel system. The document is primarily aimed at underground transit environments, including subway systems and commuter rail services that have underground sections. The generally light security currently found in transit systems, as well as the confined nature of rail tunnel systems serving large numbers of people, makes the rail tunnel system a highly vulnerable target for terrorists.]]></description>
      <pubDate>Wed, 10 Oct 2018 21:42:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1540944</guid>
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    <item>
      <title>Tunnel and Station Cost Methodology. Volume II: Stations</title>
      <link>https://trid.trb.org/View/1507619</link>
      <description><![CDATA[This report (in two volumes) describes a cost estimating methodology for subway tunnels and stations. This methodology is for the use of planners and designers interested in evaluating a realistic range for the cost of subway tunnels and stations within which the actual bid would fall. The rationale behind this cost estimating methodology is the effort to parallel the estimating process of contractors. Extensive interviews with reputable subway tunnel and station contractors and designers were conducted to identify the basic framework for estimating costs. A hierarchical cost estimating technique is developed, whereby project-specific and contractor-specific factors are identified and structured, i.e., typical advance rates are developed for a variety of geological and geometrical conditions; crew sizes (by skill) for varying geological conditions and construction methods; type and size of equipment and their associated write-off values; type of materials; contractor overhead, taxes, interest costs; etc. Finally, a data base of actual equipment, labor, materials, and lump sum costs is compiled and may be updated as changes occur.]]></description>
      <pubDate>Mon, 30 Apr 2018 19:22:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1507619</guid>
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      <title>Is there an optimum internal diameter for subway tunnels in terms of economic and technical viewpoints?</title>
      <link>https://trid.trb.org/View/1406571</link>
      <description><![CDATA[Subways, one of the most popular modes of the rapid transit systems, play an important role in maintaining the sustainability of transportation in large metropolitan areas. This study focuses on the optimum dimension of the internal diameter of subway tunnels that creates a space for train passage that is large enough to preventing collisions with electromechanical and wayside facilities and emergency walkways and is small enough to minimize costs. The discussion hinges around how a train in the worst-case situation of a super-elevated track with a minimum curve radius can pass through a tunnel equipped with wayside facilities without any accidents while satisfying all the economic aspects of the project. Limiting the speed of a train in response to the confined area between a train’s dynamic envelope and emergency walkways leads to extended travel times, excess wear on the wheel and rail and even changes in the amount of electricity consumed by the train. All the mentioned factors result in an operational cost and the total cost is achieved by summing up this cost and the construction costs for different tunnel diameters. An economic analysis is performed by comparing the costs of construction and operation for different tunnels against the benefits of passenger revenues. Generating net-present-value diagrams for tunnels with different internal diameters as a function of time shows that a double-tracked single-tube tunnel with an 8.40-m internal diameter is the optimum from both an economic point of view and being able to match technical specifications.]]></description>
      <pubDate>Fri, 20 May 2016 15:54:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/1406571</guid>
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      <title>Seismic Analysis of the Shield Tunnel Segments with Different Longitudinal Stirrup Lap Methods</title>
      <link>https://trid.trb.org/View/1338109</link>
      <description><![CDATA[There are mainly two degrees of stirrup lap used in practical engineering, which are 135-degree and 90-degree. In construction specifications, the former is used in construction which must be considered for the seismic; and the latter is designed only to meet the construction requirements. However, there isn’t any clear requirement for subway engineering. In order to analyze the influence of the two different segments longitudinal stirrup lap methods for the shield tunnels structural seismic, a new method to represent the working state of stirrups under a given situation is proposed that is by analyzing the segment’s longitudinal cracks, because the cracks mainly influence the deformation of stirrups which decides what function the stirrups provide. The calculation model of segments longitudinal force is built by using the response displacement method and the segment joint bolt deformation is also considered to be established. Finally, the method has been verified by using the finite element method (FEM) of analysis.]]></description>
      <pubDate>Sat, 14 Mar 2015 15:59:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1338109</guid>
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    <item>
      <title>Instrumentation for Tunneling Applications for Block 37 Development in Chicago</title>
      <link>https://trid.trb.org/View/1272421</link>
      <description><![CDATA[Construction of two tunnel connections at Block 37 in downtown Chicago by Chicago Transit Authority (CTA) was part of on an ambitious project linking two of Chicago's major subway lines, allowing single seat access between the two area airports, Midway and O'Hare International. The tunnel connections were located in a highly congested urban environment in downtown Chicago surrounded by historic buildings and existing subway and freight tunnels. In addition to the tunnel connection project, the development of Block 37 project included construction of a high rise building with a massive excavation adjacent to the tunnel connections. An extensive instrumentation program was installed to monitor the existing subway and freight tunnels, historic buildings, and the surrounding ground. This paper presents an overview of the instrumentation program for this project with an emphasis on the monitoring system installed in the existing tunnels and an evaluation of the final data.]]></description>
      <pubDate>Mon, 14 Jul 2014 16:50:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1272421</guid>
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    <item>
      <title>Underground Pneumatic Transport of Municipal Solid Waste and Recyclables Using New York City Subway Infrastructure</title>
      <link>https://trid.trb.org/View/1254182</link>
      <description><![CDATA[While Manhattan's streets may be the most congested--and carbon-emitting--in the country, the subway system that runs beneath them offers an inspiring example of how efficiently--and with what minimal emissions of greenhouse gases--passengers can be transported.  Although the collection and transport of municipal solid wastes produces only a fraction of the congestion and emissions on Manhattan's surface, in absolute terms the hundreds of thousands of annual truck miles these wastes cause are nonetheless quite significant.  Does the subway model offer a suggestion for how waste transport might also be revolutionized?  Perhaps. Since the now-12,000-person full-service community on the New York City's Roosevelt Island (RI) opened in 1975, none of its non-recycled, non-commercial municipal solid waste (MSW) has been collected by truck.  Instead, it is whisked from one end of the Island to the other through an underground pneumatic tube, thus saving building space, labor, and the costs and environmental impacts associated with trucks, and providing the health and quality-of-life benefits associated with the fact that unsightly bags of residential trash are not set out at curbside (as they are everywhere else in New York City) to produce odors and attract rats, pigeons, and insects. These tubes, first installed to enhance the aesthetic experience and lower the operating costs of a utopian island development, may now offer a way for New York City to significantly reduce its carbon footprint by decreasing the number of trucks in midtown Manhattan where traffic congestion and volumes of waste are greatest. Subway tunnels already carry pipe for the transportation system's energy and information needs and additional space is leased to utilities for telecommunications networks. There may also be space for a 500mm pipe like the one that carries waste under Roosevelt Island. The subway could use the system to collect passenger waste, eliminating dedicated trains for waste transport and conserving personnel time and station space for other purposes. In addition to subway waste, inlets on sidewalks and or adjacent buildings could, depending on how the system was organized, collect MSW and recyclables from pedestrians, businesses and residents. By shifting waste collection underground, trucks would no longer be required to make the sometimes daily, or nightly, trips to pick up bagged waste from sidewalks and litter baskets, or containerized waste from loading docks. Not only would there be fewer trucks on the road, reducing fuel consumption and emissions from congestion, there would be more room for other vehicles, including buses and bicyclists. If waste from ground floor retail establishments were included, there would be more room on sidewalks for pedestrians as well. By using subway tunnels this new waste management strategy could be adopted without incurring the expense and disruption associated with trenching city streets. If this initial study suggests that a pilot installation is feasible, and if a pilot project is successful, it would not only provide a model for other New York City neighborhoods, but could reduce carbon emissions in other urban areas around the State and nation.]]></description>
      <pubDate>Tue, 02 Jul 2013 01:01:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1254182</guid>
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    <item>
      <title>Dynamic Analysis of Subway Structures under Blast Loading</title>
      <link>https://trid.trb.org/View/896040</link>
      <description><![CDATA[The public transit system has become one of the targets of terrorist attacks using explosives, examples of which include the 1995 attack on the Paris subway and the 2004 attack on the Moscow subway. Under the present context of intense threats of terrorist attacks on subway systems in metropolitan areas around the world, explicit three-dimensional Finite Element method was used to investigate the dynamic response and damage of subway structures under internal blast loading. The study was motivated by the fact that explosion in subway structure may not only cause direct life loss, but also damage the subway structure and lead to further loss of lives and properties. The study used the New York subway system as background, and investigated the influences of various factors on the possible damage of subway tunnel, including weight of explosive, ground media, burial depth and characteristics of blast pressure. A mitigation measure using grouting to improve ground stiffness and strength was also analyzed. Considering the amount of explosive terrorists may use, the present study focused on small-diameter single-track tunnels, which are more vulnerable to internal blast loading and are common in New York City. Blast pressure from explosion was applied to lining surface assuming triangle pressure – time diagram, and the elasto-plasticity of ground and lining as well as their nonlinear interaction was taken into account in the numerical model. It was found from the numerical study that maximum lining stress occurred right after explosion, before the blast air pressure reduced to the atmospheric one, and it was more dependent on the maximum magnitude of air pressure than on the specific impulse, which is the area below the pressure – time curve. Small tunnels embedded in soft soil, with small burial depth, might be permanently damaged even by modest internal explosion that may be perpetrated by terrorists. The retrofit of existing subway structures and design of new ones may therefore need to seriously take into account internal blast loading if the tunnels have such characteristics.]]></description>
      <pubDate>Wed, 22 Jul 2009 15:54:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/896040</guid>
    </item>
    <item>
      <title>Tunnel Ventilation – State of the Art</title>
      <link>https://trid.trb.org/View/846239</link>
      <description><![CDATA[The use of the term tunnel in this paper refers to all transportation-related tunnels including highway tunnels, transit tunnels such as metro and subway, and railroad tunnels. From a ventilation viewpoint highway tunnels are defined as any enclosure through which vehicles travel. This definition includes not only those facilities that are built as tunnels, but those that result from other construction such as development of air rights over roads. All highway tunnels require ventilation, which can be provided by natural means, traffic-induced piston effects and mechanical ventilation equipment. Ventilation is required to limit the concentration of obnoxious or dangerous contaminants to acceptable levels during normal operation and also to remove and control some and hot gases during fire-based emergencies. The ventilation system selected must meet the specified criteria for both normal and emergency operations and should be the most economical solution considering both construction and operating costs.]]></description>
      <pubDate>Wed, 30 Jan 2008 07:35:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/846239</guid>
    </item>
    <item>
      <title>Amsterdam Metro Reaches New Depths</title>
      <link>https://trid.trb.org/View/809184</link>
      <description><![CDATA[Currently, public transportation--whether bus, tram, or metro--in Amsterdam, The Netherlands, carries approximately one million passengers each day. Ridership is expected to accelerate after 2012 when a north-south metro line opens. A major engineering challenge for Amsterdam is the country's first bored-tunnel metro line, featuring twin bored tunnels, both of which are 6.5m in diameter and 3.2 km in length. A busy city center, historic buildings, and a high water table are just some potential obstacles. Three different techniques are being employed to minimize the street level chaos and type of demolition that resulted from 1970s metro line construction. Demolition is limited by running the majority of the route under existing canals and streets; new tunneling advances make the bored tunnels technically feasible, despite a high water table and soft peat and clay layers; and city center station construction sites are covered. The author discusses facets of construction in various geographic locations, as well as safety and new trains.]]></description>
      <pubDate>Fri, 25 May 2007 10:35:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/809184</guid>
    </item>
    <item>
      <title>BAY AREA RAPID TRANSIT RETROFIT MOVES AHEAD.</title>
      <link>https://trid.trb.org/View/739744</link>
      <description><![CDATA[No abstract provided.]]></description>
      <pubDate>Tue, 15 Feb 2005 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/739744</guid>
    </item>
    <item>
      <title>THE FENWAY FLOODS OF OCTOBER, 1996: THE MBTA'S DECISIVE ACTION AND EFFECTIVE COMMUNICATIONS PRESERVE AN IMPORTANT PUBLIC SERVICE</title>
      <link>https://trid.trb.org/View/477315</link>
      <description><![CDATA[This paper examines the Massachusetts Bay Transportation Authority's (MBTA) response to a major flood of its Green Line Central Subway.  The Green Line is the MBTA's most heavily traveled and congested subway line carrying over 220,000 customers daily.  On October 20 and 21, 1996, torrential rain in excess of twelve inches fell in the Boston area. The storm overtaxed the municipal drainage systems in Boston and Brookline, and Boston's Muddy River overflowed.  Over thirty million gallons of water poured into the Green Line, crippling seven subway stations and shutting down service on portions of all four branches of the Green Line.  The tunnels were closed for six days during the pumping and emergency repair operation. During this time, the MBTA provided a variety of substitute services to meet the needs of Boston's commuters.  The article examines the organization and communication that were the cornerstone of the MBTA emergency response.]]></description>
      <pubDate>Wed, 15 Apr 1998 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/477315</guid>
    </item>
    <item>
      <title>TUNNEL CONQUERS POOR ROCK</title>
      <link>https://trid.trb.org/View/187980</link>
      <description><![CDATA[The paper reports on a variation of the thin-lining new Austrian tunneling method as the way to bore a twin-track, 2625-ft-long subway tunnel through poor rock 98 ft below a major four-lane highway without halting traffic or disturbing utility lines directly below the roadway.]]></description>
      <pubDate>Thu, 31 Mar 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/187980</guid>
    </item>
    <item>
      <title>TOKYO'S FREEZE-DRY SUBWAY TUNNEL</title>
      <link>https://trid.trb.org/View/85252</link>
      <description><![CDATA[The paper reports how freezing of soil beneath a riverbed covered with insulating plates solidifies the earth for safe tunnel excavating in a restricted site.]]></description>
      <pubDate>Mon, 11 May 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85252</guid>
    </item>
    <item>
      <title>SUBWAY DESIGNS AND CONSTRUCTION METHODS THAT CUT COSTS</title>
      <link>https://trid.trb.org/View/85251</link>
      <description><![CDATA[The author describes how the high cost of subway construction in the United States can be reduced by adopting station and track structure configurations, structural systems, and construction techniques best suited to the site geology and other constraints.  The mixed soils and high water tables generally encountered in U.S. cities, together with a highly mechanized construction industry, constrains subway design and construction.  For such conditions, estimates are provided that indicate the influence on cost of length and diameter of tunnels in different materials.  Costs of stations constructed by cut-and-cover and by tunnel-enlargement are also compared. Alternative station construction techniques are described.]]></description>
      <pubDate>Sat, 25 Apr 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/85251</guid>
    </item>
    <item>
      <title>DOWNTOWN CITY SUBWAY TUNNEL FORGES MISSING COMMUTER LINK</title>
      <link>https://trid.trb.org/View/161025</link>
      <description><![CDATA[Problems associated with the construction of a 1.7-mile cut-and-cover concrete tunnel in downtown Philadelphia, Pennsylvania on track for a run to completion in 1984 are discussed.]]></description>
      <pubDate>Wed, 18 Feb 1981 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/161025</guid>
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