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Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations (2014)

Chapter: Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook

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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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Suggested Citation:"Appendix C - Glossary of Railroad Terminology Appearing in This Guidebook." National Academies of Sciences, Engineering, and Medicine. 2014. Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations. Washington, DC: The National Academies Press. doi: 10.17226/22245.
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83 C.1 Introduction The foregoing guidebook contains numerous technical terms which may be unknown to the general reader. This glossary is meant to equip the reader with the brief definitions of these terms. Following the glossary is a listing of abbreviations and short names which appear in the guidebook. C.2 Glossary Alignment. A general term for the route taken by a rail line between two points. For example, “the alignment of XYZ railroad between A and B contains numerous curves.” In a more techni- cal sense, alignment means lateral deviations of track centerline from a true tangent or curve. FRA track safety standards 49 CFR Part 213 specify acceptable alignment deviations for each FRA Track Class. Allowable speed. Maximum speed allowed for a specific train type in a specified location. Amtrak. The marketing name for the National Passenger Railroad Corporation that operates virtually all regularly scheduled intercity passenger rail service in the United States. American Recovery and Reinvestment Act (ARRA). Commonly referred to as the Stimulus or The Recovery Act, it was an economic stimulus package enacted by the 111th United States Con- gress in February 2009 and signed into law on February 17, 2009, by President Barack Obama. Association of American Railroads (AAR). An industry association representing the interests of Class I railroads. In addition AAR subsidiaries and associated organizations are responsible for a range of activities mostly supporting freight railroading, such as industry rolling stock standards, inter-railroad freight car tracking and repair billing, and cooperative research and development. American Association of State Highway and Transportation Officials (AASHTO). A stan- dards setting body which publishes specifications, test protocols and guidelines used in highway design and construction throughout the United States. It represents air, rail, water, and public transportation as well. Aspect. See Railroad Signal and Train Control Systems. Automatic Block System (ABS). See Railroad Signal and Train Control Systems. Automatic Train Control (ATC). See Railroad Signal and Train Control Systems. Automatic Cab Signals (ACS). See Railroad Signal and Train Control Systems. Automatic Train Stop (ATS). See Railroad Signal and Train Control Systems Base Case. See Capacity and Capacity Analysis. A P P E N D I X C Glossary of Railroad Terminology  Appearing in This Guidebook

84 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations Block. See Railroad Signal and Train Control Systems. Block Authority. See Railroad Signal and Train Control Systems. Bulk Trains. See Train and Traffic Type. Capacity and Capacity Analysis. Capacity or Line Capacity is the ability of a railroad line segment to carry a given mix and volume of railroad traffic while meeting generally accepted service quality standards. Capacity Analysis is the process of estimating capacity for a specific railroad line segment. Other capacity and capacity-analysis terms are: • Base Case. An analysis of rail service performance on an existing rail corridor for the exist- ing rail traffic volume and mix. Base case analysis normally precedes analyses of the effects of changes in traffic level and infrastructure. • Grid Time Analysis. A capacity analysis method that uses travel time between passing sidings to estimate capacity in trains/day. • Latent Capacity. Available but unused capacity. • Line Capacity. See Capacity. • NCFRP Web-based Freight-Passenger Rail Corridor Project Screening Tool (SU Tool). An operations simulation program developed by the National Cooperative Freight Research Pro- gram. It is expected to be available to the public on the FRA’s website in early 2014. • Operations Simulation. A widely use, computer-based method of calculating train movements over a defined territory; it is employed for capacity analysis, operations planning, and rail invest- ment planning. Simulation usually involves step-by-step calculation of the progress of all trains over the territory based on train weight, locomotive power and braking performance, dispatcher decisions, grades, curves, signaling systems, switch types, and other factors. • Parametric Modeling. An approach to estimating capacity that relies on a simple formula with coefficients derived from regression analysis of a limited number of capacity parameters, such as siding spacing, number of running tracks and rail traffic mix, and actual observed capacity on a large number of rail line segments. • Practical Capacity. The estimated capacity of a rail line segment after adding an allowance for delays, uneven train sequencing, and unplanned events to theoretical capacity. • Rail Traffic Controller (RTC). A proprietary simulation-based capacity modeling computer package widely used by Class I freight railroads, Amtrak, and many consultants. • RAILSIM. A proprietary simulation-based capacity modeling computer package widely used by commuter railroads and rail transit systems. • RAILS2000. A proprietary simulation-based capacity modeling computer package • Simulation Modeling. See Operations Simulation. • SU Tool. Web-based Freight-Passenger Rail Corridor Project Screening Tool developed by the National Cooperative Freight Research Program (NCFRP). • String Line Analysis. A graphical method of capacity analysis that represents train movements over a line segment on a time-distance chart. • Theoretical Capacity. The estimated capacity of a rail line segment before allowing for typical train delays and uneven train sequencing. • Train Dispatch Simulator. Element in simulation modeling that mimics the behavior of a real dispatcher in routing multiple trains over rail lines. • Train Performance Calculator (TPC). Computer software that performs a step-by-step calcu- lation of the movement of a train over a specific line segment, taking into account locomotive power, train weight, braking characteristics, and speed limits but not interference from other trains. TPC’s are used to estimate pure (unhindered) running time along with other subsystems in several capacity analysis methodologies. Capitol Corridor. California passenger rail corridor running between San Jose, Oakland, Sacramento and Auburn.

Glossary of Railroad Terminology Appearing in This Guidebook 85 Carload Freight. See Train and Traffic Type. Categorical Exclusion. A category of actions in the area of environmental impact assessment that an agency has determined does not individually or cumulatively have a significant effect on the quality of the human environment (40 C.F.R. §1508.4). In the context of rail projects, such an exclusion enables a project to proceed without detailed analysis of environmental impacts. Centralized Traffic Control (CTC). See Railroad Signal and Train Control Systems. Class I Railroad. A large freight railroad having revenue exceeding an inflation-adjusted annual threshold defined by the Surface Transportation Board (STB). In 2011 the threshold was $433.2 million. Class I railroads are subject to detailed financial and operating reporting require- ments. Currently (2012) seven U.S. railroads meet Class I criteria. Class I railroads are large rail- roads having thousands of route miles of operations. Commuter Train. See Train and Traffic Type. Conflicts. A conflict arises when two opposing trains try to pass over the same section of track at the same time. Normally, the signal and train control system will prevent an actual collision. The dispatcher must determine which train has priority, and give that train authority to proceed while holding the lower-priority train until the line is clear. Control Point. See Railroad Signal and Train Control Systems. Computer-Aided Dispatching (CAD) (As distinct from Computer Aided Design used by all engineering disciplines). A system that provides a simulation of expected train movements on a railroad line segment to assist the dispatcher in determining meet and pass locations. Cool-down Period. The final period of a simulation, which can last a few hours to a full day, and which is normally disregarded as unrepresentative of train operations. Corridor. A general term used by transportation planners and analysts to describe transporta- tion facilities between two points, thus Rail Corridor, Highway Corridor or Utility Corridor. The term is often used in reference to a geographical location or specific rail service, e.g., Northeast Corridor, Capitol Corridor (CA), and LOSSAN Corridor (CA). Crew Change Location. See Crew District. Crew District. A Crew District comprises the rail territory over which train crews employed at a specific location will normally operate trains. A Crew Change Location is the point at the boundary between crew districts where crews of a long distance train are changed. Capacity analy- ses have to allow time for the change to take place and a new crew to perform required safety tests. Crossover. Track installation (including pairs or large numbers of switches) allowing trains to move from one track to another on double track. Curvature. The sharpness of a railroad curve, and the inverse of curve radius. Curvature is usually measured by railroad track engineers in degrees. A 1° curve has a radius of about 1 mile. Department of Transportation (DOT). A federal or state agency responsible for all modes of transportation. Distributed Power. The railroad practice of the placing of additional locomotives at inter- mediate points in the middle or end of the train; these locomotives are remotely controlled from the leading locomotive, to allow longer trains. Dispatcher, Dispatching and Dispatcher’s Desk. A Dispatcher is a railroad employee respon- sible for managing train movements over a specific railroad territory. Dispatching is the function performed by the dispatcher, and the Dispatcher’s Desk is the dispatcher’s workstation with

86 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations radio and other communications, switch and signal controls, and displays showing track layout, train locations, and signal and switch positions Double Track. Two main running tracks. Traditionally each track is reserved for one direction of travel. Current practice is to signal and use both tracks for bi-directional running to maximize capacity. Environmental Impact Statement (EIS). A document describing the environmental impacts of the proposed action, e.g., any adverse environmental impacts that cannot be avoided should the proposal be implemented and reasonable alternatives to the proposed action, among other things. Expedited Train. See Train and Traffic Type. Federal Railroad Administration (FRA). The federal agency with oversight responsibility for the safety of the national railway system. It also has funding authority for certain railroad projects supported with federal funds, including Amtrak funding. Federally Designated High-Speed Corridor. A designation by the FRA of corridors that have complied with certain planning requirements for high speed rail service. However, the term is outdated. The FRA now refers to express corridors, regional corridors and emerging corridors. Federal Highway Administration (FHWA). The FHWA is the federal agency responsible for the development and maintenance of the national highway system. Emphasis is on funding projects and setting standards. Freight Analysis Framework (FAF). A process used by FHWA to derive estimates of future U.S. freight transportation volumes. Fluidity. A term used by U.S. railroads to quantify the efficiency of freight operations. The usual fluidity parameter is the average speed of freight trains between freight terminals. Freight Terminal. A complex of rail yards usually near or in a major city. Freight Yard. See Yard. General Merchandise Train. See Train and Traffic Type. Grade Crossing. A location where a highway or city/local street crosses rail line at-grade. Gradient. A geographic situation in which a rail line increases or decreases elevation, usually expressed in percentages. A 1% grade is 1 foot in 100 feet. Grid Analysis. See Capacity and Capacity Analysis. Host Railroad. An owner of a rail line segment over which one or more other railroads have rights to operate a defined service. Most often used to describe a freight railroad that hosts Amtrak or a commuter service. Horsepower per Ton (hp/ton). See Power-to-Weight Ratio. Hours of Service. Railroad employees in safety sensitive positions including train crews are subject to FRA-mandated Hours of Service regulations governing lengths of a work shift and mandatory rest periods between shifts. In Slot. An opening circumstance in which a train takes its planned place in a sequence of trains operating over a specific rail line segment. Interlocking. See Railroad Signal and Train Control Systems. Joint Powers Authority (JPA). An institutional arrangement for multiple local government entities to combine to finance and manage a passenger rail service, or for another qualifying purpose.

Glossary of Railroad Terminology Appearing in This Guidebook 87 JPAs are common in California. In other states, similar institutions can be implemented through interlocal agreements. Intermodal Train. See Train and Traffic Type. Latent Capacity. See Capacity and Capacity Analysis. Light Engine Movement. A light engine movement means that a locomotive or locomotives not coupled to a train are moving over a rail line, usually to reach their next train assignment or a servicing location. Line Capacity. See Capacity and Capacity Analysis. Line Side Signals. See Railroad Signal and Train Control Systems. Line Speed. Maximum speed at a specified location. Some train types may be required to operate at below line speed. Local Freight Train. See Train and Traffic Type. LOSSAN. Name applied to a 351-mile corridor running from San Luis Obispo in the north to San Diego in the south, along California’s Pacific Coast. Main Line. A rail line segment connecting two points on a railroad network used by long dis- tance trains. Manifest Train. See Train and Traffic Type. Meet. Trains travelling in opposing directions passing each other at a passing siding Midwest Regional Rail Initiative (MWRRI). A collection of rail corridors totaling 3,000 route miles and nine Midwestern states that would host new or enhanced passenger rail services. Chi- cago would serve as the unifying hub of the system. The concept was earlier described as the “Chicago Hub Network.” Monte Carlo Randomization Methods. An analysis method that involves repeated calcula- tions of a specific analysis where some inputs are selected from a probability distribution rather than having a single value. The results of the calculation are usually expressed as statistics of selected outputs. Monte Carlo methods are used in capacity analysis to account for the effects of unscheduled train operations and typical service disruption. Moving Blocks. See Railroad Signal and Train Control Systems. National Environmental Policy Act (NEPA). A federal Act that requires environmental reviews of most federally funded passenger rail and other major investment. Northeast Corridor (NEC). A major passenger rail corridor between Boston and Washington, DC, via New York City, Philadelphia, and Baltimore. The entire corridor is electrified. Its use is shared by Amtrak, various commuter rail operators, and freight railroads. Amtrak owns most of the corridor. On-Time Performance (OTP). A widely used measure of passenger rail service quality, usually expressed as arrival delay statistics, e.g., percentage of trains arriving within X minutes of sched- uled time. Freight railroads also track on-time performance, most commonly with expedited intermodal or premium service trains. Operations Simulation. See Capacity and Capacity Analysis. Overtake. See Pass. Pad or Schedule Pad. Difference between the scheduled time for a specific rail journey and the minimum travel time (pure running time) to adjust for statistically normal delays.

88 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations Parametric Modeling. See Capacity and Capacity Analysis. Pass. When a train overtakes another train traveling in the same direction at a passing siding. Passenger Rail Investment and Improvement Act (PRIIA). A federal act, signed into law in 2008, that governs passenger rail policy and funding from 2008 to 2013. Passenger Terminal. A major passenger station usually with dead-end or stub-ended tracks. Passenger Train. See Train and Traffic Type. Positive Train Control (PTC). See Railroad Signal and Train Control System. Power-to-Weight Ratio. Refers to the ratio of locomotive horsepower and total train weight (horsepower/ton), and is the key parameter in calculating train acceleration and achievable speed. See also Tractive Effort and Tractive Effort Curve. Practical Capacity. See Capacity and Capacity Analysis. RAILSIM. See Capacity and Capacity Analysis. Rail Safety Improvement Act (RSIA). The 2008 federal rail legislation that, among other pro- visions, requires the installation of PTC on lines carrying regularly scheduled passenger service and selected hazardous materials. Railroad Signal and Train Control Systems. General term applying to methods used by rail- roads to ensure safe and efficient train operations. Individual signal and train control systems and elements in common use and referenced in this report are: • Aspect. The aspect is the color or pattern of a wayside light signal providing a specific message to a train operator. Commonly, a green light means “all clear,” an amber light means “approach” (warning that the next signal may be a stop signal), and a red light means “stop.” The railroad’s Rule Book will define signal aspect meanings, which can differ between railroads and some- times between railroad regions. • Automatic Block System (ABS). A system of dividing a rail line into discrete blocks, typically 2 to 10 miles in length, entry to which is controlled by color-light signals (block signals) that automatically indicate whether the block is occupied by a train. A red signal indicates that the block is occupied and another train should not enter. • Automatic Train Control (ATC). A system that continuously monitors train speed using elec- tric or electronic control technology and automatically applies train brakes when the engineer fails to respond to signal indications to stop or reduce speed. • Automatic Cab Signals (ACS). A system that displays a duplicate of wayside signal indications in the engineer’s cab, using electric or electronic communication technology. • Automatic Train Stop (ATS). A system that applies train brakes when the engineer fails to respond to a more restrictive signal indication. Unlike ATC there in no continuous monitor- ing of train speed. • Block or Signal Block. A length of track between block or interlocking signals. Normally only one train is permitted to occupy a block. • Block Authority. Permission given to a train to enter and occupy a signal block. This permission is transmitted to the train’s engineer by a voice radio message, a train order, a wayside signal indication, or is automatically transmitted to the engineer’s cab by a PTC system or automatic cab signals. • Centralized Traffic Control (CTC). A system where switches and associated signals are con- trolled by a dispatcher in a remote control center. • Control Point. Location of remotely controlled switches and signals in a CTC system. • Interlocking. An installation, originally mechanical but now electrical or electronic, at a siding or junction that ensures safe coordination between signals and switch positions.

Glossary of Railroad Terminology Appearing in This Guidebook 89 • Line Side Signal. A color-light signal positioned alongside the track that provides movement authorities to train operators. Line side signal is an alternative term for wayside signal. • Moving Blocks. An advanced train control approach where spacing between trains is defined by safe braking distance plus a safety margin for the specific train and train speed at the time. Fixed signal blocks are not used. • Positive Train Control (PTC). A train control system that will automatically enforce authori- ties, speed limits, and work zone restrictions if the engineer fails to operate the train correctly. A detailed description is provided in Appendix B. • Shunt. An electrical connection between rails through the wheel and axle set of a train, com- pleting a track circuit and activating automatic block signals and other train control systems. • Signal Block. See Block above. • Track Circuit. Electrical circuit used to detect the presence of a train in a signal block. • Track Warrant. A formal order issued to a train engineer on an unsignaled line segment authorizing a train movement between defined locations. Track warrants are usually recorded on a control center database that prevents a dispatcher from issuing confliction warrants. • Train Control System (TCS). An alternative term for CTC used by some railroads. • Wayside Signal. See Line Side Signal above. Rail Traffic Controller (RTC). See Capacity and Capacity Analysis. Reverse Running. An operating practice on double track where each track is signaled for one direction of running. Reverse running is when train direction is opposed to the normal direction, usually at lower speed and under manual rather than signal control. Restricted Speed. Defined in railroad rule books as a speed from which a train can stop in half the visible distance and not to exceed 15 or 20 mph, depending on local requirements. Restricted speed operations are normally permitted on unsignaled yard tracks and after stopping at a block signal. Record of Decision (ROD). The formal acceptance by the responsible authority of an Envi- ronmental Impact Statement (EIS) after completion of all legal requirements. Root Cause. A term used to describe the depth in the causal chain where an intervention could reasonably be implemented to change performance and prevent an undesirable outcome. Schedule. A list of train departure and arrival times used by a railroad both for internal opera- tions management and to communicate with passengers and freight service customers. Scheduled Service. A rail passenger or freight service that operates on a fixed, pre-announced schedule, as distinct from trains that operate on an as-needed basis. As-needed freight operations are a common practice in the U.S. Sealed Corridor. A passenger rail corridor where the risk of a collision with a highway vehicle is minimized by closing as many grade crossings as possible, and installing high-performance crossing safety systems on all remaining crossings. This safety approach was initially applied to a rail corridor in North Carolina, and later applied elsewhere. Service Outcomes Agreement (SOA). An agreement between host and tenant railroads speci- fying service quality parameters, such as journey time and on-time performance, that the host railroad guarantees it will provide a tenant railroad. Usually, the host is a freight railroad and the tenant a passenger service. Shared-Use. This term refers to the use of rail corridor by multiple train or service types, most commonly passenger and freight trains. Related terms are as listed below: • Shared Corridor. A rail corridor shared by two or more types of rail service, usually passenger and freight. This term is rarely used in reference to a corridor shared only by different types of freight service.

90 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations • Shared Track. Where passenger and freight trains operate on the same track. • Shared Right-of-Way (ROW). A rail corridor where passenger and freight service operate over separate parallel tracks in a transportation corridor but do not normally interconnect. This frequently applies to shared ROW where the primary rail corridor is for FRA-regulated, “generally-connected” (conventional) passenger or freight trains and the parallel use is by lighter (non-FRA-compliant) rail transit, such as light rail or heavy rail metro/rapid-transit. Shunt (as in track circuit). See Railroad Signal and Train Control Systems. Siding. A track parallel to a main running track with switches at each end used to allow pass- ing and overtaking movements. Signal Block. See Railroad Signal and Train Control Systems. Simulation Modeling. See Capacity and Capacity Analysis. Single Track. A line segment with one main running track. Sidings are needed to allow passing and overtaking train movements. Slow Order. A formal requirement, usually issued by the engineer responsible for track con- struction and maintenance on that segment, that limits train speed at a specific location. Slow orders may be permanent, for example, for a sharp curve; or temporary, for example, pending repair of a track defect. Spur. A track branching off a main track to provide access to a yard, terminal or line side industrial plant. State of Good Repair. The state of a rail line segment or corridor when all track defects have been corrected and life-expired structures and other installations have been replaced or rebuilt. State Sponsored Service. An intercity passenger rail service that receives financial support from a state government authority or from a coalition of states. String Line. See Capacity and Capacity Analysis. Super-elevation. The banking of railroad track in a curve. Super-elevation is usually expressed as the height of the outer rail over the inner rail in inches and is incorporated into the track struc- ture as a function of curvature and train speed. Switch. A switch is a track installation where a single track divides into two tracks. Switch blades (tapered lengths of rail) can be moved laterally so that a rail vehicle moving over the switch can be directed to either track. Switch (blade) position can be controlled locally by a manual lever, or by an electrically powered switch motor from a remote location. Terminal. See Passenger Terminal and Freight Terminal. Theoretical Capacity. See Capacity and Capacity Analysis. Track Circuit. See Railroad Signal and Train Control Systems. Track Warrants. See Railroad Signal and Train Control Systems. Tractive Effort. The horizontal force a railroad locomotive can exert on a train at its coupler. Tractive effort of a diesel-electric locomotive depends on horsepower, train speed, and its electri- cal control characteristics. Tractive Effort Curve. The variation of tractive effort with speed. See Tractive Effort. Train Control System (TCS). See Railroad Signal and Train Control Systems.

Glossary of Railroad Terminology Appearing in This Guidebook 91 Train Consist. The rolling stock making up a train, e.g., numbers and types of locomotives and freight cars or passenger cars. Train Crew. On-board railroad employees responsible for train operations, usually compris- ing engineer, conductor, and sometimes one or more trainmen (a.k.a., assistant conductors) to assist with passenger train doors, ticket checks, and switching operations. The conductor is the leader of the train crew. Train Dispatch Simulator (TDS). See Capacity and Capacity Analysis. Train Mix. The mix of train types operating on a line segment. Train Performance Calculator (TPC). See Capacity and Capacity Analysis. Train Sequencing. The order in which trains follow one another through a line segment. Usu- ally determined by a dispatcher to maximize capacity while meeting service quality requirements. Train and Traffic Type. A general term that distinguishes trains and rail traffic by type of rail service provided or type of commodity carried. Because of differing maximum speeds, train lengths, and power-to-weight ratios, train type is an important input to rail capacity calculations. The principal types are: • Bulk Train. A train carrying a single bulk commodity, similar to a unit train as defined below. • Carload Freight. Rail freight operation that moves single carloads of freight from origin to destination via classification yards and local and long distance general freight trains. • Commuter Train. A passenger train providing shorter distance service (generally under 100 miles), usually in a large metropolitan area. Commuter trains typically make frequent stops (e.g., every 5 or 6 miles). • Expedited Train. Any train operated on a faster, more tightly defined schedule. An expedited train will have a higher priority for meets and passes. • General Merchandise Train. A train carrying a mix of freight types between classification yards. • Intercity Passenger Train: A passenger train (typically Amtrak) providing medium to longer distance service (generally over 100 miles) between metropolitan areas. Intercity passenger trains typically make stops between 25 and 100+ miles apart, depending on population density. • Intermodal Train: This train carries intermodal shipping containers or highway trailers. Because such freight is often time-critical, intermodal trains typically have higher power-to- weight ratios and maximum speeds. • Local Freight Train: A train moving loaded or empty cars to or from a classification of switch- ing yard to individual industry tracks. • Unit Train: Unit trains carry a single commodity from origin to destination without interme- diate switching, and usually return empty to the point of origin. Power-to-weight ratios and speeds are typically low. A majority of unit trains carry coal between mines and power plants. Other unit train or bulk commodities are grains and metal ores. • Manifest Train: A scheduled general merchandise train. Universal Crossover. A crossover comprises a pair of switches on a double track line to allow a train to move off one track and onto the adjacent track. A universal crossover is a pair of cross- overs that allows trains moving in either direction to cross to the adjacent track without making a back-up move. Warm-up Period. The initial period of a simulation, which can last a few hours to a full day, and which is normally disregarded as unrepresentative of train operations. Wayside Signals. See Railroad Signal and Train Control Systems.

92 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations Yard. An array of tracks, usually unsignaled, where passenger and freight trains and cars are sorted, serviced and stored. On most railroads, specific operating rules apply to yard operations, including Restricted Speed requirements. Classification yards or switching yards are where gen- eral merchandise trains are assembled from cars gathered from local shippers, or broken down for local delivery. Storage yards are where railcars are stored. Intermodal yards lift trailers or containers onto or off of railcars. Yard Lead. A track leading into and out of a yard, where trains can wait until track is available to exit the yard onto the main line or for continuing yard activities. C.3 Abbreviations Listed below are abbreviations appearing in the guidebook. Definitions are cited in the preced- ing section. Freight railroad and other abbreviations and short names used in this guidebook appear below as well. AAR. Association of American Railroads. ABS. Automatic Block System. ACS. Automatic Cab Signals. ARRA. American Recovery and Reinvestment Act. AASHTO. American Association of State Highway and Transportation Officials. ATC. Automatic Train Control. ATS. Automatic Train Stop. CAD. Computer-Aided Dispatching (vs. more commonly, “Computer-Aided Design”). CCJPA. Capitol Corridor Joint Powers Authority. CSV. Comma Separated Values. CTC. Centralized Traffic Control. DOT. Department of Transportation. EIS. Environmental Impact Statement. FAF. Freight Analysis Framework. FHWA. Federal Highway Administration. FRA. Federal Railroad Administration. HSIPR. High Speed Intercity Passenger Rail. JPA. Joint Powers Authority. LOSSAN. LOSSAN Rail Corridor. MP. Milepost. MWRRI. Midwest Regional Rail Initiative. NCFRP. National Cooperative Freight Research Program. NEPA. National Environmental Policy Act.

Glossary of Railroad Terminology Appearing in This Guidebook 93 NEC. Northeast Corridor. OTP. On-Time Performance. PRIIA. Passenger Rail Investment and Improvement Act. PTC. Positive Train Control. RAILS2000. The Railway Analysis and Interactive Line Simulator. ROD. Record of Decision RSIA. Railroad Safety Improvement Act. RTC. Rail Traffic Controller. SOA. Service Outcome Agreement. SU. Shared-use, as in SU Tool. TCS. Train Control System. TDS. Train Dispatch Simulator. TPC. Train Performance Calculator. TPS. Train Performance Simulator. Freight Railroad Abbreviations BNSF. BNSF Railway. CN. Canadian National Railway. CP. Canadian Pacific Railway. CSO. Connecticut Southern Railroad. CSXT. CSX Transportation. IC. Illinois Central Railroad, now part of CN. NS. Norfolk Southern Railway. PANAM. Pan Am Railways. P&W. Providence and Worchester Railroad. UP. Union Pacific Railroad. Other Abbreviations or Short Names ACE. Altamont Commuter Express commuter rail service in Northern California. BART. Bay Area Rapid Transit. Caltrain. Commuter rail service on San Francisco Peninsula and in Santa Clara County. Caltrans. California Department of Transportation. COASTER. Commuter rail service in San Diego County. ConnDOT. Connecticut Department of Transportation. CSI. Corporate Strategies Inc. IDOT. Illinois Department of Transportation.

94 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations LAUS. Los Angeles Union Station. MARC. Maryland Area Regional Commuter rail service. Metra. Chicago area commuter rail service. Metrolink. Los Angeles area commuter rail service. NCDOT. North Carolina Department of Transportation. NCTD. North County Transit District running COASTER trains. NHHS. New Haven-Hartford-Springfield. NJ Transit. New Jersey Transit offering commuter rail services. OCTA. Orange County Transportation Authority, member of SCRRA. ODOT. Oregon Department of Transportation. PennDOT. Pennsylvania Department of Transportation. SCRRA. Southern California Regional Rail Authority running Metrolink trains. SEPTA. Southeast Pennsylvania Transportation Authority. SLE. Shore Line East commuter service in southern Connecticut. Sounder. Commuter service along the Puget Sound in Washington State. Sound Transit. Seattle area transit agency running Sounder trains. USDOT. United States Department of Transportation. VRE. Virginia Railway Express. WSDOT. Washington State Department of Transportation.

Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S.DOT United States Department of Transportation

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TRB’s National Cooperative Highway Research Program (NCHRP) Report 773: Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations provides state departments of transportation with technical guidance to aid in their understanding of the methods host railroads use to calibrate and apply capacity models. The guidebook examines the modeling processes and results that are used to define, measure, simulate, and evaluate railroad capacity. These models may help determine if adequate capacity exists to support new or increased passenger rail service or if infrastructure improvements may be necessary.

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