Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide (2009) / Chapter Skim
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Pages 51-76
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From page 51... ...
While their diverse operations and situations also offer a range of experience, a review of the results reveals common traits and challenges facing transit systems planning or operating service where light transit equipment shares track with conventional railroad trains. An extensive review of findings can be found in the report prepared for Task 5.
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From page 52... ...
1) Public Ownership and Control The transit authority typically purchases the service line, makes infrastructure improvements necessary for higher speed/higher frequency passenger operation, and then provides freight access to the satisfaction of the former owner of the line.
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From page 53... ...
track operation generally requires the freight railroad to relinquish dispatching and maintenance control, the participation of freight rail owners gives freight interests a strong voice in determining when freight service will take precedence. Some freight service schedule adjustments may be necessary, but it is the transit authority that must attempt to accommodate the freight carrier's needs, or else risk having the process stalled.
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From page 54... ...
The shared section of track was sufficiently short to permit the entire segment to be designated as one interlocking. Specialized signaling equipment fulfills the fail-safe train separation requirement while allowing freight trains to operate between light rail trains, under the supervision of the Transit Authority.
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Antioch, CA) wanted to operate noncompliant vehicles to allow for interoperability with existing systems.
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– Ridership impacts. – Alternatives evaluation-ridership and cost estimates are used as output measures.
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Physical Characteristics Data collection begins with a description of the physical characteristics of the existing and proposed new corridor. This includes length, grades, curves, grade crossings, bridges and tunnels, sidings, crossovers, terminals, stations, facilities and other salient features.
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can use a radial mainline railway for line-haul transport from the suburbs, and then continue or switch to local street-running tracks to serve the downtown destinations, and other routing options are possible. Historically nearly all SPRCs have used on-board diesel engines for power, and have been capable of operation as a train with a single train or with multiple cars.
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From page 59... ...
b. The lower acceleration and braking rates of compliant DMUs are not conducive to the frequent stops required for an effective downtown service design.
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Cost and Ridership Analyses An important part of any project study is collection, comparison and analysis of data describing capital and operating costs for traditional transit development and for shared-track alternatives. 60 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide Table 9.
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The study should explore cost savings and other benefits to the community afforded by concurrent shared-track choices as transit development options are evaluated. A bottom-up approach to costing is suggested.
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• Automated train stop (intermittent, inductive implementation) : Consists of a basic CTC signal system plus a two-aspect ATS system implemented as described in Option 2, based on block signaling principles.
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From page 63... ...
of ASC systems must be done on a case-by-case basis, factoring in such variables as number of interlockings, vehicles to be equipped, track miles, and what other systems are in use regionally for interoperability reasons. Research emphasizes that it is preferable and less costly to use commercial-off-the-shelf systems and components rather than advanced state-of-the-art technology.
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From page 64... ...
options. Cost savings in shared track accrue mainly from subgrade, track, structures, and design work.
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Estimated freight shortline revenues and operating expense. Table 15 allows for the comparison of a forecast of annual freight operating revenues and expense for four typical options and the status quo (i.e., null alternative -- no changes, no system)
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These riders may be diverted to other parts of the service day. Alternatives Evaluation Ridership and cost forecasts are integrated to provide three key performance measures to rank and evaluate the service options shown in Table 17.
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And the safety case is essential to support the business case. Risk Analyses Template Introduction A simplified risk analysis is provided to estimate the relative risk of casualties to train occupants in train accidents for each of the four alternative options defined.
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From page 68... ...
The risk analysis methodology shown is an adaptation of that used and fully described in a recently completed (but not yet published) report to the FRA, "ITS Technologies for Integrated Rail Corridors." The analysis is intended to convince a transit authority considering a concurrent shared-track operation with light rail passenger cars and low density conventional freight that a safety performance acceptable to FRA can be achieved, and that such projects are worth further development.
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From page 69... ...
to other parties, for example highway users at grade crossings or trespassers, the risks to these parties is minimally affected by the different forms of track sharing and have not been included in the analysis. There are two categories of specific hazards or accident scenarios described in this analysis: I
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From page 70... ...
to select units of measurement for risk that properly represent the kinds of harm that underlie the motive for the risk analysis. In this case the primary concern is the chance of injuries and fatalities among train occupants as a result of train accidents.
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Route, traffic and ridership data. Basic route information was taken from the descriptions earlier in this chapter.
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Table 21. Exposure of passenger trips to freight activity.
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. The process that was summarized previously offers these results: • Proposed operation exceeds safety requirements typical of the transit industry; and • Proposed operation has a lower estimated risk than stand alone light rail system (Option 2)
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From page 74... ...
Results of the Sample Case Study In this example, congruent results of the business and safety cases are integral to concluding that a shared-track project is feasible for the defined circumstances. Positive indications are: • In terms of capital cost, proposed shared track operation is more economical than a separate and parallel (stand-alone)
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Achievable Incremental Steps The incremental approach now has a credible foundation. Furthermore as regulators and policy makers gain more experience with sharing track, these examples can be replicated in other settings.
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From page 76... ...
Practical Shortcuts For Shared-Track One goal of this research is to identify means to safely permit a limited cotemporaneous operation via a combination of technology and procedures. To be acceptable, a concurrent operation of light rail passenger cars and freight cannot increase risks or hazards to the operation, employees, passengers or the public, above those experienced in an operation served by compliant passenger and freight equipment.
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