Web-Based Screening Tool for Shared-Use Rail Corridors (2014) / Chapter Skim
Currently Skimming:
Pages 24-59
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 24... ...
24 3.1 Introduction and Study Objectives The purpose of this chapter is to summarize the findings from the research associated with developing a Web-based tool to enable states and passenger rail operators to perform preliminary feasibility screening of proposed shared-use passenger and freight rail corridor projects. The screening tool would be intended to • Support preliminary feasibility analysis of rail passenger projects and identify those that warrant further detailed investigation with more rigorous analytic tools.
|
From page 25... ...
25 (the "AAR Study")
|
From page 26... ...
26 The next section summarizes findings from the inventory of tools and methodologies. 3.2.1 Parametric Approaches Parametric approaches use empirically calibrated formulas rather than equations derived from first principles to establish relationships between infrastructure, train volume, traffic mix, delay, and capacity.
|
From page 27... ...
27 simplest representative of this class of model is the wellknown equation for estimating the capacity of a single-track rail line: C T -= 12 ( ) Equation 3 1 where C = the capacity of the line in trains per day, each direction T = the running time of the single-track segment, in hours It is easy to extend this capacity framework to develop tables of slot-based capacities for both single and multiple tracked rail line.
|
From page 28... ...
28 Finding: The main advantage of topological approaches is their ability to identify directly the bottleneck section(s) of a rail line, pointing directly to the locations where infrastructure additions may be the most needed.
|
From page 29... ...
29 and interconnected. Contemporary simulation models also facilitate displaying, zooming, and scrolling time-distance diagrams and have sophisticated and high-quality animations.
|
From page 30... ...
30 The research team also noted the following findings regarding relevance to a Web-based SU screening tool: • Possible viable approaches include analytic, topological, and simulation-based tools. – Simulation is an evaluative approach that can assess the effectiveness of capacity solutions that have been defined for it.
|
From page 31... ...
31 The following sources are publicly available and can be used to directly determine or infer a corridor's rail facility data in lieu of or supplementing the sources listed above: • U.S.DOT FRA GIS 1:100000 Rail Network Database (source: BTS) ; • Oak Ridge National Laboratory Center for Transportation Analysis Rail Network Database; • U.S.DOT FRA Highway-Grade Crossing Database (source: Office of Safety Analysis)
|
From page 32... ...
32 This method of data collection does not provide sufficient detail to determine system entry and exit points or timetable routes. To fulfill the preliminary data requirements listed above, the data collection process discussed in this section will have to supplement other sources of rail infrastructure data.
|
From page 33... ...
33 survey and used to supplement the traffic volume data from the FRA Grade Crossing Database. Traffic mix.
|
From page 34... ...
34 cooperative freight railroad might be willing to supply the needed traffic data on request. 3.4.4 Infrastructure Costs Experience indicates that it is highly likely that additional infrastructure or upgrades will be required to accommodate the needs of both freight and passenger operations.
|
From page 35... ...
35 Finding: Unit cost data is available from other studies, but will require adjustments for inflation and regional conditions. 3.5 Case Studies: Corridor Selection and Key Findings For evaluating the SU tool developed with this project, the research team proposed five potential shared-use corridors, each with different levels of commuter, intercity, and freight traffic.
|
From page 36... ...
36 the requirements of the FRA Guidance Manual (1) and the analysis is limited by the level of data that is either publicly available or that can be obtained by state DOTs for screening capacity needs.
|
From page 37... ...
37 time. The simulator needs to test a specific infrastructure plan to see whether freight train delays have increased or decreased from baseline levels and to ensure that delays remain at acceptable levels.
|
From page 38... ...
38 • A determination of how long to make the sidings needs to be made as follows: – If trains are not expected to run precisely on time, then exact meet/pass locations cannot be precisely determined in advance. For example, because the departure time variability of freight trains often exceeds the running time between sidings, this probabilistic approach is often followed in laying out freight infrastructure (38)
|
From page 39... ...
39 As a result, it should be clear that the conflict identifier approach has been developed into an evolved methodology for suggesting the level of capacity that needs to be added to a shared-use corridor. The range of application has been extended well beyond the light-density, single-tracked lines to which Ideal Day methodology was originally applied.
|
From page 40... ...
40 infrastructure and train databases, therefore, closely follow the structure of the earlier assessment, in order to develop a consistent comparison. • For the infrastructure database, the data files that were used as the basis of the original St.
|
From page 41... ...
41 updated to reflect some improvements that have occurred since 2004 (e.g., the Gasconade River bridge) but does not include the Osage River Bridge that, although funded, has not been completed as of the time of this report.
|
From page 42... ...
42 – However on the single-tracked Sedalia Subdivision west of Jefferson City, there are a total of nine passenger-onpassenger train meets. Because each passenger train meet affects two different passenger trains, this count is multiplied by two, so 18 meets divided by the 12 daily passenger trains yields an average of 1.5 meets per train.
|
From page 43... ...
43 Figure 3-4. Summary of St.
|
From page 44... ...
44 on weekdays. There are, on average, 110 passenger trains and 20 freight trains operating on the territory on a typical weekday.
|
From page 45... ...
45 • The Crescent, which runs from New York to New Orleans; and • The Silver Service, which runs from New York to Miami. MARC and SEPTA provide local commuter rail services with MARC's Penn Line operating between Baltimore and Perryville, and SEPTA operating between Wilmington and Newark.
|
From page 46... ...
46 route to quadruple track; thus allowing double track for highspeed Amtrak use and two tracks for shared use between local commuter and freight trains, as shown in Figure 3-5. By upgrading the Baltimore to Newark segment to quadruple track and connecting to existing quadruple track north of Newark, Amtrak would be able to expand its operations to the level desired in its proposed plan.
|
From page 47... ...
47 will determine the suitability of existing infrastructure to accommodate existing traffic, which by assumption also should accommodate the alternative future traffic containing a different mix of freight (+16) and passenger (-30)
|
From page 48... ...
48 future case -- Step 4 -- will indicate degraded service, e.g., increased delay)
|
From page 49... ...
49 Figure 3-9. Baltimore to Wilmington -- future case string line, 12 a.m.–8 a.m.
|
From page 50... ...
50 explore this potential. A summary of this analysis is shown in Figure 3-12.
|
From page 51... ...
51 Rail operations along the Milwaukee to Chicago study corridor are shared among commuter, intercity passenger, and freight services. For a short distance between Chicago Union Station and Lake Street, Amtrak controls the line while Metra dispatchers operate the line from Lake Street to Western Avenue.
|
From page 52... ...
52 timetable speeds along the corridor range from 70 to 79 mph according to the data in the FRA National Grade Crossing Inventory. Currently, the study corridor handles a significant volume of commuter, freight, and intercity rail passenger traffic.
|
From page 53... ...
53 assumed they are mostly short locals serving industrial customers along the line. North of Techny to Milwaukee, the FRA National Grade Crossing Inventory reports 18 daily freight trains, or 9 trains in each direction.
|
From page 54... ...
54 1 to 3 trips per day (68) while reducing travel times by up to 30 percent (69)
|
From page 55... ...
55 commuter, in addition to expanded passenger, train service on the corridor. The case adds freight trains along with the 19 planned additional passenger round trips.
|
From page 56... ...
56 • Although the data requirements of a parametric tool are minimal, they are actually not sufficiently tailored to local conditions to produce a credible corridor-specific screening assessment. • An optimization-based tool is not likely to prove useful for addressing the needs of a Web-based screening tool.
|
From page 57... ...
57 • The screening tool also provides a simulation tool that can be used to both validate and support the credibility of the results of conflict identification. The simulation capability is provided as a core feature of the SU tool and has been demonstrated in the case studies.
|
From page 58... ...
58 Figure 3-17. Summary of SU analysis, Chicago-Milwaukee Corridor.
|
From page 59... ...
59 – The NEC study was undertaken as a double-blind exercise without a validation benchmark. However the results of both the conflict identification and simulation screening indicate the potential feasibility of restoring full Norfolk Southern freight service (daytime as well as nighttime)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.