Transit Capacity and Quality of Service Manual, Third Edition (2013) / Chapter Skim
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From page 446... ...
1. User's Guide 2.
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From page 447... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 5.
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From page 448... ...
Transit Capacity and Quality of Service Manual, 3rd Edition LIST OF EXHIBITS Exhibit 8-1 Basic Train Signal Operation ........................................................................................... 8-4 Exhibit 8-2 Distance-Time Plot of Two Consecutive Trains ......................................................
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From page 449... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Exhibit 8-36 Typical Moving-Block Station Headways Compared with Conventional Fixed-Block Systems .................................................................... 8-51 Exhibit 8-37 Peak-Period Station Dwell Times for Heavily Used Systems (1995)
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From page 450... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Exhibit 8-73 Example Sketch-Plan String-Line Diagram (Charlotte North Corridor Commuter Rail)
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From page 451... ...
Organization of Chapter 8. At a minimum, be familiar with the content of Sections 2 and 3 before applying this chapter's computational methods.
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From page 452... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Refinements to the general methodology are subsequently presented for commuter rail and automated guideway transit (AGT) lines, and a separate method is presented for estimating the capacity ofropeway modes (e.g., aerial trams and funiculars)
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From page 453... ...
Ideally, station dwell time and the minimum train separation produced by the signaling system will control line capacity, but other factors may need to be considered. Line capacity and vehicle capacity, both relating to the number of trains that can be operated per hour, are equivalent terms for rail capacity.
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From page 454... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Stat ion Train D-D-0-0 • t-e R t-0G Block t-0G t-0G 1. Signals turn red behind a train as it enters each block D-D-0-0 • t-e R t-e R t-0G t-0G 2.
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From page 455... ...
Exhibit 8-2 Distance-Time Plot of Two Consecutive Trains Transit Capacity and Quality of Service Manual, 3rd Edition the following trains and, consequently, is an important component of line capacity. Operating margins are discussed further in Section 5.
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From page 456... ...
Transit Capacity and Quality of Service Manual, 3rd Edition operators, and through passenger education efforts to encourage passengers to step aside to allow others to exit the train first and to not hold train doors open. Guideway Characteristics Turn backs A typical terminal station will have a center (island)
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From page 457... ...
Exhibit 8-4 Types of Rail Junctions Exhibit 8-5 At-Grade ("Flat") Junction Operation Transit Capacity and Quality of Service Manual, 3rd Edition 1.
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From page 458... ...
Transit Capacity and Quality of Service Manual, 3rd Edition • The physical configuration of the platform: its width, length, curvature, usable area for passenger queuing and circulation, and configuration and capacity of vertical circulation; • The rate at which passenger alight from and board the train; • The extent of any horizontal gaps between train door sill and the platform edge or differences in elevation between the platform and the car floor-which affects the rate at which passengers board and alight; • The time required to open and close the train doors; and • Operational procedures affecting the boarding process. Ideally, platforms should have tangent (straight)
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From page 459... ...
Person capacity defined. The theoretical capacity is the number of cars per hour per direction, times the maximum design load of each car.
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From page 460... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Loading Diversity Passengers do not load evenly into cars and trains over the peak hour. Three different types of loading diversity have to be considered: (a)
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From page 461... ...
Loading diversity within the peak hour. Exhibit 8-7 Example A.M .
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From page 462... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Number of Cars The number of cars in a train is a major determinant of person capacity-the longer the train, the more people it can carry. However, there are limits to how many cars can be added to a train, set by the lengths of platforms, the supply of cars, and (for light rail)
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From page 463... ...
Exclusive lanes can mitigate street block length constraints. Train signaling systems are discussed in detail in Section 3.
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From page 464... ...
Transit Capacity and Quality of Service Manual, 3rd Edition assumptions) , the unique acceleration and braking characteristics of each train type, and the dwell times at each scheduled station stop within the span of the control line.
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From page 465... ...
Exhibit 8-9 Illustrative Capacity as a Function of Speed for a Rail Transit Line Transit Capacity and Quality of Service Manual, 3rd Edition Calculated capacity at a given signal that does not factor in these variable elements is often referred to as the calculated or theoretical capacity at that signal location. Each of the variables not included in theoretical capacity can have a negative effect on capacity in one of two ways: 1.
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From page 466... ...
Transit Capacity and Quality of Service Manual, 3rd Edition For rail transit systems, the speed at which capacity is maximized is in the range of 25 to 30 mi/h ( 40 to 50 km/h, usually significantly lower than the allowable top speed) , and the peak throughput usually is in the range of 30 trains per hour (equivalent to an approximate 2-min headway)
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From page 467... ...
Exhibit 8-10 Conceptual ReliabilityThroughput Relationship Transit Capacity and Quality of Service Manual, 3rd Edition High Low 10 12 14 16 18 20 22 24 26 28 30 32 Throughput (trains/h) Transit and rail lines that are asked to deliver a level of throughput close to their theoretical capacity can expect to be less reliable than those that are planned to operate at longer headways.
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From page 468... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 3. TRAIN CONTROL AND SIGNALING OVERVIEW The role of signaling is to safely separate trains from each other and protect specific paths through interlockings (switches)
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From page 469... ...
Conventional train control systems can support a throughput of 30 trains/track/hour. Cab signaling sets authorized, safe train speeds.
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From page 470... ...
Transit Capacity and Quality of Service Manual, 3rd Edition command the train to brake, accelerate, or coast accordingly. The target point will be based on the normal braking distance for that train plus a safety distance.
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From page 471... ...
Automated train operation systems often also provide for manual operation. Automated train operation may provide a 2 to 4% capacity increase.
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From page 472... ...
Transit Capacity and Quality of Service Manual, 3rd Edition opposed to shared-use lanes with general traffic. While streetcars can also operate in separate transitways, most streetcar operations share lanes with general traffic and tend to institute transit signal priority in a similar manner as buses due to their shorter train length (typically only one vehicle)
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From page 473... ...
Exhibit 8-11 On-Street Rail Preferential Treatment Examples Transit Capacity and Quality of Service Manual, 3rd Edition intersection before servicing the station. In these cases, there should preferably be at least one lane available for parallel general traffic, so that motorized vehicles do not queue up behind a stopped train and block the intersection.
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From page 474... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 4. TRAIN OPERATIONS OVERVIEW The previous section focused on the effects of train control and signaling on the capacity of a rail transit line.
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From page 475... ...
Exhibit 8-12 Selection of Rail Transit Door Flow Times (1995) Data in this exhibit are illustrative of the range of values that are possible.
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From page 476... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Medium-volume level doorway High-volume level doorway Low-floor light rail Light ra il with steps Light ra il with steps and onboard fares 0 1 2 3 4 Time per passenger per single stream (s) I D Boarding • Alighting • M ixed Flow Sources: TCRP Report 13 (1)
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From page 477... ...
Special event passenger rates were found to be slower than weekday peak rates. Operating margin examples.
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From page 478... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 400 350 300 ..
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From page 479... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Exhibit 8-16 Dwell Train Estimated Dwell and Headway Average Standard Average Dwell as Control Operating Data Summary of Station and Station Deviation Headway %of Separation Margin Surveyed Rail Transit System and City Direction Dwell(s)
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From page 480... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Vancouver-Met rotown EB (off-peak) 59 -143 I I I I San Francisco BART-Embarcadero WB 81 ..
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From page 481... ...
Skip-stop operation increases average speed but not capacity. Skip-stop service tries to balance loads between the "A" and "B" trains.
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From page 482... ...
Transit Capacity and Quality of Service Manual, 3rd Edition TRAIN AND PLATFORM SCREEN DOORS Many AGT systems and newer heavy rail transit systems have platforms that are enclosed and separated by screens from the guideway, with doors that open directly adjacent to the train doors when the train stops at the platform. The door opening mechanisms are coordinated so that the platform and train doors open and close simultaneously.
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From page 483... ...
Exhibit 8-18 Onboard Fare Collection Platform width. Inadequate platform exit capacity can reduce line capacity, as dwell times of following trains increase.
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From page 484... ...
Transit Capacity and Quality of Service Manual, 3rd Edition NFPA 130 requirements may not be met on older systems. Additional exits must be provided to ensure that exit throughput is not constrained by platform back-ups.
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From page 485... ...
Impact af wheelchairs an line capacity. Mixed use af high and law platforms.
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From page 486... ...
Transit Capacity and Quality of Service Manual, 3rd Edition (a) On-street station in median (San Francisco)
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From page 487... ...
Exhibit 8-21 Mini-High Platforms Profiled platform os on alternative to mini-high platforms. Exhibit 8-22 Profiled Light Rail Platform Providing for One Accessible Door Transit Capacity and Quality af Service Manual, 3rd Edition Low-floor cars provide much of the benefit of level loading without the need for high platforms.
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From page 488... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Maximum Rise Maximum Slope Rise :53 in.
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From page 489... ...
Exhibit 8-25 Car-Mounted Lifts Bridgeplates are often used to span the gap between platform and train. High-level platforms are usually nat possible an lines shared with freight trains.
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From page 490... ...
Transit Capacity and Quality of Service Manual, 3rd Edition (a) Vancouver (b)
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From page 491... ...
Crossovers can be used to short-turn trains to help recover from delays. Transit Capacity and Quality of Service Manual, 3rd Edition system operation, (b)
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From page 492... ...
Transit Capacity and Quality of Service Manual, 3rd Edition >DODD< 'CCJciDD7 Store tra in on pocket track Store train on siding xCJDDCJ: s ~ Store tra in beyond terminal station Move train to yard =cJOf Turn t rai n at crossover The spacing of storage tracks and crossovers requires balancing initial capital costs when constructing the system with the amount of delay a system is willing to tolerate when a train breaks down. Physical constraints, particularly when tracks are elevated or underground, must also be considered.
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From page 493... ...
Use of express tracks. Crowd management.
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From page 494... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 5. RAIL SYSTEM CAPACITY METHODOLOGIES INTRODUCTION Except for the simplest of operations, or for operations that have a long history of experience, there are no "one-size-fits-all" formulas for calculating the capacity of a rail corridor.
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From page 495... ...
A spreadsheet that implements the general rail capacity methodology is provided on the accompanying CD-ROM. Consider using the planning graphs in Section 6 when input variables must be defaulted.
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From page 496... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Default Value Calculated 650ft, 200m 35ft, 10m Calculated 88 ft/s, 27.8 m/s 75% 2.4-three-aspect, 1.2-cab, 1.0-moving block 3.0 s 0.5 s 0% 0% 90% 20.5 ft, 6.25 m 165ft, 50 m Term Description t~ train control separation (s) Lt longest train length (ft, m)
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From page 497... ...
Exhibit 8-30 Typical Station Headways for Lines at Capacity Exhibit 8-31 Maximum Speed Limits on Curves Curves and turnouts (switches) impose speed restrictions.
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From page 498... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Lateral Turnout Eguilateral Turnout Turnout Number mi/h km/h mi/h km/h #6 15 24 21 34 #8 20 32 28 45 #10 25 40 35 57 #20 50 81 70 113 Source: AREMA Manual for Railway Engineering (8)
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From page 499... ...
Exhibit 8-34 Typical Effect of Grade on Station Headway Exhibit 8-35 Typical Headway Changes with Voltage Transit Capacity and Quality of Service Manual, 3rd Edition 150 145 140 3: 135 > 111 3: 130 "l:l 111 Cll 125 ::1: 120 / / , ./ , / .......
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From page 500... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Fixed-Block and Cab Signaling Throughput The minimum train control separation for fixed-block and cab signal systems is given by Equation 8-1, with variables as shown in Exhibit 8-28: _ 2(Lc +deb)
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From page 501... ...
Exhibit 8-36 Typical Moving-Block Station Headways Compared with Conventional FixedBlock Systems Capacity is higher with a moving-block signaling system. Compare the approach speed producing the minimum train separation to any speed restrictions an the station approach.
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From page 502... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Four methods of estimating dwell time or controlling dwell time are provided in this section. The first method is the one used in most of the literature references-simply assigning a reasonable figure to the critical station.
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From page 503... ...
Exhibit 8-37 Peak-Period Station Dwell Times for Heavily Used Systems (1995) Transit Capacity and Quality of Service Manual, 3'd Edition Passengers Mean Mean Headway System & City Station Observed Dwell(s)
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From page 504... ...
Transit Capacity and Quality of Service Manual, 3'd Edition The closer the trains operate, and the busier they are, the more chance there is of minor incidents delaying service due to an extended station dwell time, stuck door, or late train ahead. It is never possible to ensure that delays do not create interference between trains, nor is there any stated test of reasonableness for a specific operating margin.
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From page 505... ...
Single track reduces capital costs but can add a serious capacity constraint. This constraint only applies to two-way operation, not to one-way operation, such as on a downtown one-way street grid.
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From page 506... ...
Transit Capacity and Quality of Service Manual, 3rd Edition The minimum single-track headway is: hst = 2tst where t st = time to cover single-track section (s) , and h st = minimum single-track headway (s)
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From page 507... ...
Scheduling for single trock. Passing sections.
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From page 508... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Equation 8-7 can be used to determine the minimum headway between trains operating on-street in exclusive lanes or mixed traffic (1, 10)
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From page 509... ...
Additional time may need to be allowed when grade crossings adjacent to station exits are manually activated. Equation 8-8 Equation 8-9 Transit Capacity and Quality of Service Manual, 3rd Edition Delays to other roadway users caused by premature activation of crossing gates and signals at near-side stations can be reduced using wayside communication equipment.
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From page 510... ...
Transit Capacity and Quality af Service Manual, 3rd Edition Step 3: Determine the Limiting Junction Headway Correctly designed junctions should not be a constraint on capacity. Where a system is expected to operate at close headways, high-use junctions perform more reliably and at higher levels of capacity if they are grade separated.
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From page 511... ...
Although 120-s headways are possible, junctions generally should be grade separated for headways below 15G-180 s. Advantage of sophisticated supervision to reduce junction conflicts.
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From page 512... ...
Transit Capacity and Quality of Service Manual, 3rd Edition The worst case is based on the arriving train (lower left) being held at the crossover approach signal while a train departs.
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From page 513... ...
Exhibit 8-44 Light Rail Single-Track Terminus with Separate Unloading Platform Dual-faced platforms and loops can reduce dwell times. Transit Capacity and Quality of Service Manual, 3rd Edition 21 mi/h (34 km/h)
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From page 514... ...
Transit Capacity and Quality of Service Manual, 3rd Edition the front cab. Once the train has been readied for departure and received its boarding passengers, it can depart without further delay.
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From page 515... ...
Equation 8-13 Equation 8-14 Equation 8-15 The PHF ranges from 0.25 (all volume occurs during the peak 15 min) to 1.00 (volumes are even throughout the hour)
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From page 516... ...
Transit Capacity and Quality of Service Manual, 3rd Edition whenever possible; when these data are not available, the following default PHF values for specific modes can be used instead: • 0.80 for heavy rail, • 0.75 for light rail, and • 0.60 for commuter rail operated by electric multiple-unit trains. System (City)
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From page 517... ...
Push-pull commuter rail operation. Transit Capacity and Quality of Service Manual, 3rd Edition space per passenger as low as 3.2 ft2 (0.3 m2)
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From page 518... ...
Transit Capacity and Quality of Service Manual, 3rd Edition capacity calculations. For comparison, a typical diesel Amtrak intercity train has a P /W ratio of 4 to 6, while electric high-speed corridor trains (such as the Metroliner used in the Washington-New York-Boston corridor)
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From page 519... ...
Transit agency ownership of track used for commuter rail. Transit Capacity and Quality of Service Manual, 3rd Edition • Track deterioration requiring temporary speed restrictions, • Passenger station stops, • Industrial switching, • Freight yard interactions, • Train or train control system failures, • Incidents (e.g., crossing accidents, deer, and trespassers)
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From page 520... ...
Transit Capacity and Quality of Service Manual, 3rd Edition but rather an efficiency issue with respect to equipment and staff utilization. Unidirectional operation is an issue on lines where reverse commuting to suburban work sites is important.
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From page 521... ...
Dwells are less critical far commuter rail than for heavy rail transit. Exhibit 8-47 Multiple-Platform Commuter Rail Terminal Examples Platform level and commuter rail car door layout.
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From page 522... ...
Transit Capacity and Quality of Service Manual, 3rd Edition center of the car, as on New Jersey Transit, the South Shore in Chicago, and the DeuxMontagnes line in Montreal. Most hi-level and gallery cars are designed for low platforms and have the lowest step close to the platform for easy and rapid boarding and alighting.
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From page 523... ...
Increasing the siding entry speed may also require improvements to the siding itself. Improving track conditions to improve train speeds may not improve capacity if blocks have to be lengthened to accommodate faster trains.
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From page 524... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Other infrastructure issues can create capacity constraints (1) : • junctions are often under the control of different dispatchers, requiring a train to be held at a junction, blocking the exit.
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From page 525... ...
AGT has nuances that must be considered when applying the generalized rail transit capacity methodology. Transit Capacity and Quality of Service Manual, 3rd Edition capacity based on 90% of a seated load is a reasonable value that reserves capacity to accommodate higher-than-average passenger demands on a given trip.
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From page 526... ...
Transit Capacity and Quality of Service Manual, 3'd Edition surrogate of this can be roughly simulated by setting the train detection uncertainty factor Bat four times the minimum braking distance. The results are shown in Exhibit 850 for trains of typical AGT lengths, using the specific AGT values in Exhibit 8-51, with terms adjusted from typical rail transit values shown in bold.
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From page 527... ...
AGT loading levels tend to be atypical of transit overall. Off-line stations increase capacity.
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From page 528... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Surface modes include some of the oldest mechanized purely urban transportation systems, discounting extensions of intercity rail networks into city centers. Vehicles are either permanently attached to the rope, or can attach and detach from the rope by means of a grip mechanism.
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From page 529... ...
See Chapter 2 for descriptions and illustrations of the various ropeway modes. Equation 8-17 Manufacturers' stated capacities typically do nat account for loading diversity.
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From page 530... ...
Transit Capacity and Quality of Service Manual, 3rd Edition PHF accounts for the system's inability to fill every seat in every vehicle, as some capacity is reserved to handle surges in passenger demand. Changing the person capacity of aerial ropeway systems is difficult, because the infrastructure (e.g., towers, rope size, vertical clearances)
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From page 531... ...
Design for mature capacity. The planning procedures require two main inputs: (a)
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From page 532... ...
Transit Capacity and Quality of Service Manual, 3rd Edition The necessary choices are only two, the type of train control system and the train length. The range is provided by assigning (a)
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From page 533... ...
Exhibit 8-54 Capacity of Light Rail Systems Designed for Minimum Planned Headway A three-aspect fixed-black system typically can support na mare than 30 trains per hour-and less if a line has flat junctions or a station with extended dwell times. Transit Capacity and Quality of Service Manual, 3rd Edition In these cases, line capacity is directly related to the signaling constraint built into the system (assuming no significant single-track sections)
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From page 534... ...
Transit Capacity and Quality of Service Manual, 3'd Edit ion 52 50 48 :2 46 ........
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From page 535... ...
Exhibit 8-57 Grade-Separated Line Capacity-MovingBlock Signaling Transit Capacity and Quality of Service Manual, 3rd Edition 52 so 48 46 ~ 44 ........
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From page 536... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Single Track Single-track sections with two-way operation will typically be the capacity constraint when they are present. Exhibit 8-59 provides the directional line capacity of single-track sections of various lengths, with and without stations within the singletrack section.
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From page 537... ...
Exhibit 8-61 Light Rail Line Capacity-Exclusive Lane Operation Exhibit 8-62 Light Rail Person Capacity-Exclusive Lane Operation Exclusive lane, an-street operation is unlikely to be the capacity constraint when traffic signal cycle lengths are relatively short. Transit Capacity and Quality of Service Manual, 3rd Edition Exclusive Lane Operation The minimum sustainable headway in exclusive lane on-street operation is typically twice the longest traffic signal cycle length.
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From page 538... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Private Right-of-Way with Grade Crossings This category includes railroad-type operations, with street crossings controlled by gates, and operations within street medians, with street crossings controlled by traffic signals. When trains have full preemption of traffic (e.g., at gated crossings, or when full signal preemption is provided at traffic signals)
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From page 539... ...
Exhibit 8-64 Gondola Person Capacity Transit Capacity and Quality of Service Manual, 3rd Edition Continuously Circulating System Capacity The line capacity of a continuously circulating system is dependent solely on the spacing of carriers or vehicles on the line. Person capacity, therefore, is simply a function of line capacity, vehicle size, and passenger arrival characteristics.
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From page 540... ...
Transit Capacity and Quality of Service Manual, 3rd Edition • Transit vehicle fleet requirements (and associated capital costs) : determining the most appropriate equipment type and the number vehicles required (including spare/ out-of-service allowances)
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From page 541... ...
Transit Capacity and Quality of Service Manual, 3rd Edition ROLE OF SIMULATION Definition and Applicability An operations simulation model realistically depicts train movements over a transit or railroad network, including main lines, junctions, stations, and terminals. Simulations are powerful analytic tools that accurately represent: • The physical characteristics of the infrastructure of a transit or railroad network, • The performance characteristics of the trains operating on the network, and • The signaling/train control system that governs operations of trains within the network.
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From page 542... ...
Transit Capacity and Quality of Service Manual, 3'd Edition required rail corridor upgrades and to estimate travel times before the interference effects from other trains and other typical operating delays are taken into account. For initial planning, it is customary to pad the minimum trip time by around 10 percent to estimate a practical trip time.
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From page 543... ...
Exhibit 8-66 Example Dynamic Dispatch Animation: Washington Union Station Transit Capacity and Quality of Service Manual, 3rd Edition WaShington Unloo Station A single run of a corridor operations simulation will only represent operations under one set of input conditions. Railroad operations are subject to a variety of random and planned disruptions to normal operation, including planned and unplanned track maintenance, delays at stations, and delays caused by events elsewhere on the railroad.
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From page 544... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Simulation Software Features There are several simulation software packages available for use in railroad and rail transit operations analysis. Simulation software packages are similar in the way that they display simulation results.
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From page 545... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Event-based models do not simply resolve conflicts between pairs of trains, but rather look globally at multi-train conflicts and resolve them as integral elements in the dynamics of the entire network. These models can be equipped with "meet-pass" dispatching logic, which is used to develop the most effective solutions to single-track operations requiring segments with a second main track, passing tracks, or passing sidings.
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From page 546... ...
Transit Capacity and Quality of Service Manual, 3rd Edition out into separate reports and track occupancy charts for review and analysis) ; and • Detailed train schedule for the time period to be analyzed.
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From page 547... ...
Exhibit 8-67 Example Speed Profile Transit Capacity and Quality of Service Manual, 3rd Edition Boston Montr .. l High Speed Rail Local Consist: 6 cars ( 6L + OE)
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From page 548... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Tnck 1 Tnck2 Tnck3 Tnc:k4 Train colors D Track16 D Track17 D LIRRWSSY • New Haven line • LIRRW • LIRRE 0 Amtrak Empire • Brews1er • AmtrakNEC D NJTEasl t -- -- -- -- + -- -+ -- -+ -- -""' -- -- -+ -- -- '-; -- -t • NJT W•SI TnckS ~-.. -~-+ -- -+ -- -+ -- -~-.a~ -- ~ -- ~ - p~ Tnck6 Tnck7 Tnck8 Tnck9 Tnck 10 Tnck 11 Tnck 12 Dynamic Visual Representation Outputs Dynamic dispatch animation presents a "real time" dynamic visual representation of the railroad's operation of the railroad depicted in the simulation.
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From page 549... ...
Exhibit 8-69 Dynamic Dispatch Animation Example: Penn Station New York Transit Capacity and Quality of Service Manual, 3rd Edition Et.0401 CMJ.ol Et.tJ351 EMJJ5.: Et41l.JJ APPLICATION OF SIMULATION Base Case Model Calibration and Validation The simulation model will first need to be calibrated and validated to reflect a realistic representation of the scheduled running times for the operations and services being analyzed. The first step in the process is to build a base case computer simulation I model that includes all the parameters required by the model for the analysis, including the rail infrastructure characteristics, rolling stock characteristics, and operational service levels for the territory being analyzed.
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From page 550... ...
Transit Capacity and Quality of Service Manual, 3rd Edition solutions to respond to the assumed or desired frequency or level of service. The model is used to : • Establish operational feasibility, • Prove the reliability of the operation, and • Identify order of magnitude of capital costs for infrastructure and fleet.
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From page 551... ...
Exhibit 8-70 Example Simulated lnterlockings Exhibit 8-71 Example Network Graphic with Crossovers Transit Capacity and Quality of Service Manual, 3rd Edition Construction Staging and Maintenance-Of-Way Windows The model provides the ability to develop realistic construction staging plans and to schedule the most effective maintenance-of-way (MOW) time slots on busy main tracks and terminals.
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From page 552... ...
Transit Capacity and Quality of Service Manual, 3'd Edition Single-Track Networks Significant capital and maintenance cost savings sometimes can be realized in light density railroad and transit operations by operating service over a single main track on all or a portion of a line. These savings, however, come at the expense of capacity and operational flexibility.
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From page 553... ...
Exhibit 8-73 Example Sketch-Plan String-Line Diagram (Charlotte North Corridor Commuter Rail) Transit Capacity and Quality of Service Manual, 3rd Edition inspecting string-line diagrams and track-occupancy diagrams, and by adjusting train schedules, track assignments and train performance to resolve conflicts.
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From page 554... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Washington Union Station Platform Track Occupancy Existing PM Peak, 3:00PM-6:00PM 7 8 8b 9 9b 10 11 12 12b 13 14 14b 15 15b 16 16b 17 18 19 20 23 24 25 26 27 28 -- ~r -- i -- -i -- -i -- -i -- -t -- -t.~~~~ -- -r -- -r -- -r -- -r -- -r -- + -- -+ -- -t -- -r.~~~7,,;~r -- -r -- ir -- i -- t -- -t -- -r -- -r.~~~ 15:10 IS: IS 15:45 """ "~ 16:00 16:10 16:15 16:20 16:25 .!
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From page 555... ...
Exhibit 8-76 Example Sketch-Plan Train Loading Chart (California High Speed Rail) Transit Capacity and Quality of Service Manual, 3rd Edition Passenger loadings- Peak Hour(lndividual Trains)
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From page 556... ...
Transit Capacity and Quality of Service Manual, 3rd Edition operating plans for a range of alternatives. In this approach, operations planning tools are developed at two levels of detail : system-level sketch planning and detailed simulations of actual infrastructure and operating conditions.
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From page 557... ...
Transit Capacity and Quality of Service Manual, 3rd Edition • Operating performance characteristics, by train type and train, for the deterministic base case and any alternative delay or perturbation scenarios analyzed, including extent, location, and causes of delay; • Equipment cycles and revenue/protect equipment/spare fleet requirements; • Crew schedules and train and engine crew requirements; • Overnight and midday storage yard utilization; • Train performance calculations for each train type and stopping pattern; and • Rolling stock consists, length, top speed, acceleration/deceleration profiles, and other relevant characteristics. The output from the ridership forecasts, when these are available, will be used as feedback to the operations planning process to optimize the level of service for the forecast years for which projections are provided.
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From page 558... ...
Transit Capacity and Quality of Service Manual, 3'd Edition 7. CALCULATION EXAMPLES Example Description 1 High-capacity heavy rail 2 Heavy rail line with junction 3 Heavy rail with long dwell 4 Light rail with single-track section 5 Commuter rail with limited train paths 6 AGT with short trains 7 AGT with off-line stations 8 Aerial ropeway CALCULATION EXAMPLE 1: HIGH-CAPACITY HEAVY RAIL The Situation A transit agency is planning to build a heavy rail transit line and wants to determine the minimum train separation possible with a cab signaling system and with a variable safety distance moving-block signaling system.
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From page 559... ...
Exhibit 8-78 Calculation Example 1: Input Data Compare the approach speed producing the minimum train separation with any speed restrictions an the station approach. Value calculated 600ft 35ft 47 ft/s (cab)
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From page 560... ...
Transit Capacity and Quality of Service Manual, 3'd Edition tcs = 12.4 + 13.6 + (0.387)
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From page 561... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Step 8: Determine Person Capacity In the absence of a specific vehicle, the text accompanying Step 8 in Section 5 indicates that a recommended comfortable heavy rail car loading for a new system is 1.8 passengers per linear foot of train length, inclusive of diversity allowances. At this loading level, each specified train of eight 75-ft-long cars can carry 8 x 1.8 x 75 = 1,080 passengers.
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From page 562... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Value Term Description Calculated hi limiting headway at junction 31.2 s tcs line headway, from Calculation Example 1, Step 1b(2) 600ft Lt train length 9.62 !
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From page 563... ...
Exhibit 8-80 Calculation Example 3: Input Data Transit Capacity and Quality of Service Manual, 3rd Edition • There is a 1.5% downgrade into the station and a 1.5% upgrade out of the station. • The line is automated and uses moving-block signaling.
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From page 564... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Substituting the variables into Equation 8-3 produces: Lt + Pe ( 1 )
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From page 565... ...
Exhibit 8-81 Calculation Example 4: Input Data Transit Capacity and Quality of Service Manual, 3rd Edition Multiplying 1,080 pjtrain by 33 train/h gives a person capacity of approximately 35,000 passengers during the peak hour in the peak direction through this station (rounded down to the nearest 1,000 to reflect the approximations used)
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From page 566... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Substituting these results into Equation 8-5 produces: [(Nst + 1)
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From page 567... ...
Transit Capacity and Quality of Service Manual, 3rd Edition bus bridge around any blockage that is expected to take a significant time to clear. All North America light rail operators also have or are affiliated with major bus operations and can expect to obtain buses and drivers for such emergency use on short noticeusually by scavenging buses from nearby high-frequency routes.
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From page 568... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Single-level cars The effective capacity per car is 90% of 120, or 108 passengers. An eight-car train of single-level cars could thus carry 864 passengers.
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From page 569... ...
Transit Capacity and Quality of Service Manual, 3rd Edition and operating margin values of 40 and 25 s respectively would result in a minimum headway of 78.4 s, which would normally be rounded up to 80 s to provide an integer number of trains per hour. Section 5 states that head ways shorter than 90 s are possible but may limit dwell times and constrain the operating margin.
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From page 570... ...
Transit Capacity and Quality of Service Manual, 3rd Edition • The developer has contracted with the office building tenants to run trains at least every 6 min until midnight each day, including weekends and holidays. Computational Steps To handle 24,000/3 + 1,200 = 9,200 passengers per hour, one solution would be to operate longer trains with higher occupancy and to omit stops in the office buildings with their short stations.
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From page 571... ...
Transit Capacity and Quality of Service Manual, 3rd Edition The Questions 1. For the aerial tramway, how large will the carriers need to be to handle the projected passenger demand?
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From page 572... ...
Transit Capacity and Quality of Service Manual, 3'd Edition meaning that it would only travel 260 ft at line speed (2,600-ft line length, minus two times 1,170 ft)
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From page 573... ...
Transit Capacity and Quality of Service Manual, 3rd Edition provide the required number of hourly station arrivals is 105 arrivals per hour divided by 9.47 arrivals per carrier per hour, or 12 carriers (rounded up)
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From page 574... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 8.
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From page 575... ...
Transit Capacity and Quality of Service Manual, 3rd Edition 13. Schaefer, B
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From page 576... ...
Transit Capacity and Quality of Service Manual, 3rd Edition APPENDIX A: EXHIBITS IN METRIC UNITS 80 70 60 ::2 .......
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From page 577... ...
Exhibit 8-36m Typical Moving-Block Station Headways Compared with Conventional FixedBlock Systems Exhibit 8-39m Light Rail Travel Time Over Single-Track Section Transit Capacity and Quality of Service Manual, 3rd Edition 170 \ 160 150 3 140 > !
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From page 578... ...
Transit Capacity and Quality of Service Manual, 3rd Edition Average Operating Speed (km/hl Station Spacing (km) P/W=3.0 P/W = 5.8 P/W = 9.1 Average Dwell Time= 30 s 1.6 I 27.0 32.7 35.9 3.2 I 41.5 49.7 56.4 6.4 I 58.6 71.0 78.2 8.0 I 64.9 78.4 84.8 Average Dwell Time= 60s 1.6 I 23.8 28.0 30.3 3.2 I 37.5 44.1 49.3 6.4 I 54.4 65.0 71.0 8.0 I 60.9 72.5 78.1 Source: Galloway (12)
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From page 579... ...
Exhibit 8-59m Single-Track Line CapacityTwo-Car Light Rail Trains Exhibit 8-GOm Single-Track Person Capacity-Two-Car Light Rail Trains Source: Note: Source: Note: Transit Capacity and Quality of Service Manual, 3rd Edition 30 25 ...
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From page 580... ...
Transit Capacity and Quality of Service Manual, 3'd Edition ...
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Key Terms
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