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Shared-Track: A Handbook of Examples and Applications 61 Table 11. Worksheet 5--Typical operating regime and corresponding service scenarios. Option 1 2 3 4 Operating Strict Temporal Spatial Concurrent Concurrent Regime Separation Separation Single Track Double Track Passenger Service Headways Initial: Peak 15 15 15 15 Off-peak 30 30 30 30 Best Possible: Peak 15 15 15 5 Off-peak 15 15 30 15 Maximum: Off-peak headways Peak Headways shorter than every "X" min requires new of less than "Z" Off-peak sidings min require Headways shorter than every "Y" min requires double- dedicated freight tracking sidings Passenger Hours of Service Initial: First Train Out 6:00 am 5:00 am 5:00 am 5:00 am Last Train In 7:30 pm 1:30 am 1:30 am 1:30 am Maximum: First Train Out 5:00 am 24 hour service 24 hour service 24 hour service Last Train In 7:45 pm Freight Operating Windows 9:00 am 3:59 9:00 am 3:59 7:30 pm 5:59 pm pm Initial 24 hour am 7:00 pm 5:59 7:00 pm 5:59 am am X, Y and Z will vary to suit the circumstances. The study should explore cost savings and other benefits to the community afforded by concur- rent shared-track choices as transit development options are evaluated. A bottom-up approach to costing is suggested. The transit system infrastructure and invest- ment options should be broken down into components. The unit cost of each component can be calculated based on construction contracts, engineers' rules-of-thumb, and aggregate costs of labor and materials. To compute the unit cost of service delivery, take direct labor plus overhead using industry-average labor and overhead costs, and apportionment from known operating costs of comparable systems. Total cost is derived by summing component costs, then adding a percentage for indirect costs and contingencies. Electric light rail projects proposed for FTA New Starts are typically more expensive than the sample system considered here. Additional costs such as real estate acquisition, planning and permitting, and electric traction infrastructure are not considered in this desktop analysis. Nonetheless, the analysis underscores the magnitude of savings available to local transportation officials who consider a shared track alternative. Cost Analysis for Signal System Alternatives Rough cost comparisons can be made between generic families of signal systems when applied to the same operation. There are a variety of available sources to arrive at an approximate per-mile cost estimate for systems similar to a proposed shared-track operation. Each basic train control regime should be considered: Centralized traffic control (CTC) with wayside signals: A basic, traditional CTC railroad signal system with remote controlled power interlockings, cables, track circuits, control center console, insulated joints, impedance bonds, wayside automatic signals with 2.5 miles on average between interlockings, typical of configurations under temporal separation.

OCR for page 61
62 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide 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. Freight train movement authorities are enforced by signal interlocked derails. Multi-aspect inductive intermittent speed supervision: A CTC signal system overlaid with a three-or-four-aspect Automatic Speed Control (ASC) system. Continuous supervision of train speeds is not provided, but trains are positively protected against signal overruns. It is sufficient for Options 3 and 4 if a suitable vehicle-borne apparatus can be installed on freight locomotives. Automated speed control with enforced digital cab signals (continuous, coded or audio frequency track circuit implementation): This technology is standard for modern light rail implementation. The system provides for continuous speed supervision based on cab signal aspects and may provide train-to-wayside data communication capabilities. Wayside signals are not installed except at interlockings. It is sufficient for Options 3 and 4. Communication-based train control with speed enforcement: This is an emerging technol- ogy for which no production examples have been fully implemented. Wayside signals are not installed except as backup. Systems adapted for Options 3 and 4 would have the same enforce- ment and display capabilities as a coded track-circuit system and would provide continuous supervision of speeds. A summary of average cost per track-mile for these systems is presented in Table 12. As shown in the table, commercial-off-the-shelf train control systems are perfectly suitable and more appropriate for shared-track rather than advanced state-of-the-art technology. A cursory examination of signal costs reveals that the two ASC options appear to cost between 25% and 100% more than the unprotected CTC options. Considering signal costs alone, both multi-aspect intermittent speed control and digital coded track-circuits with ASC capability seem to provide the necessary functionality at similar costs. The intermittent systems provide a cheaper per-signal cost but have a higher per-cab cost, whereas the coded track circuits require more expensive wayside infrastructure but the cab-borne equipment can be simpler and cheaper. Appendix 4 provides additional "Relative Cost of Train Control Systems" information. Intermittent systems (Row 3 in Table 12) are used on some rapid-transit cab signal territories: on New York City Transit, the NJ Transit River LINE, and some legacy commuter rail and rail- road lines in the Midwest. Both systems are proven and expertise to design and maintain both types of systems can readily be found in the United States The choice between these two families Table 12. Range of unit costs for families of signal technology. Average Total System Cost per Cost per Track Mile Passenger Signaling Technology ($ Million) Cost per Signal or Block Cab 1 Centralized Traffic $7,500 for wayside color $1.6 None Control light signals 2 Two-Aspect Automated $7,500 for waysides + $1.8 $60,000 Train Stop $6,000 per trip stop 3 Multi-Aspect Inductive $7,500 for waysides + Intermittent Speed $10,500 to $15,000 per $80,000 to $2.1 to $3.2 Supervision signal $120,000 for transponders 4 Automated Speed Control No waysides enforced with Digital Cab $1.9 to $3.0 $10,000 to $30,000 per $50,000 Signals "signal" 5 Communication-Based No waysides More than $2.1 to $5.0 Train Control Not signal based $100,000