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Analysis and Modeling 37 Rail Traffic Controller Software Package RTC simulates train movements over a rail corridor by mimicking the behavior of a skilled dispatcher, given rail traffic volume and mix, track layout, signal system, etc. A TPC module cal- culates train progress over the corridor in response to signal indications and dispatcher commands. Results of each model run are presented as traffic flow animations, time-distance (string-line) charts, train delay statistics (the primary measure of whether capacity is adequate), TPC outputs, and various train operating statistics, such as average speed (velocity). The model can be used to evaluate the sensitivity of corridor performance to traffic level and mix, evaluate benefits from capital improvements, design a train schedule, and identify bottlenecks or capacity constraints and options for removing them. Almost all the U.S. Class 1 railroads have standardized on RTC and have prepared infrastructure and operations data for entry into RTC for much of their route network. The principal advantage of the RTC package for freight railroads is that it is specifically designed for North American freight operations and fully accounts for the characteristics of such operations. It has been adapted to user experience to make it the leader for U.S.-style freight operations. RAILSIM Software Package RAILSIM is the second widely used software package for train operations simulation. Applications of this software have mainly been to higher-density and complex commuter and rail transit operations, to plan optimum track and signal system layouts, and to minimize delay potential and energy consumption. RAILSIM was recently used to plan Caltrain commuter ser- vice developments between San Francisco and San Jose, California, a predominantly passenger corridor with limited local freight service. It is also widely used in the New York City region on predominately commuter corridors, such as the Long Island Railroad, Metro-North Commuter Railroad, and New Jersey Transit, and in the Chicago area by Chicago Metropolitan Rail (METRA) and Northern Indiana Commuter Transportation District (NICTD). 3.2.3 Using Simulation and Modeling in Rail Corridor Planning and Negotiations The recommended approach to applying rail operations simulation, analyzing the capacity of a shared corridor, and determining the infrastructure investments needed to provide a defined freight and passenger service is discussed in the following subsections. Step 1. Agree on What Type of Analysis is Required and What Model to Use The first step in any operations simulation modeling is to agree on what kind of analysis is required and what simulation package will be used. The kind of analysis will depend on the com- plexity of operations on the corridor. A corridor with simple operations--such as four or five daily passenger round trips, a daily local freight train, and three or four through freight trains that run to a predictable schedule--should not need complex modeling. Instead, a simple train performance calculation and string-line time-distance plots should be sufficient to plan passing siding locations and where track upgrades to increase speeds are worthwhile. A corridor with more trains, trains with different priorities, and long-distance through trains with unpredictable schedules will require more advanced analysis. As indicated earlier, it will be most cost and time effective to use the train operations software package routinely used by the host railroad to analyze operations on the corridor. The freight railroad will likely already have prepared train and infrastructure data for the model, greatly reducing the effort needed to prepare for analysis. Almost all Class 1 freight railroads have stan- dardized on the RTC model, so it is highly likely that the best choice for capacity and infrastruc- ture investment analysis for a new passenger rail service on a busy Class 1 rail corridor will be the

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38 Guidebook for Implementing Passenger Rail Service on Shared Passenger and Freight Corridors RTC package. Stakeholders report that freight railroads consider RTC to give the most reliable capacity analysis available and are very reluctant to accept results from alternative models as a basis for estimating capacity requirements of a proposed passenger service. Passenger rail agen- cies that have participated in RTC-based capacity analysis report that they have been satisfied with the results and the resulting decisions regarding the need for capacity investments. The situation will be similar on a busy commuter rail corridor (often used by an intercity pas- senger service for final miles into a city center), except that the software package of choice is more likely to be RAILSIM. Smaller host railroads (for example, a non-Class 1 freight rail or a smaller commuter operation) will likely not have previously conducted detailed operations simulation analyses; if detailed analysis is necessary, the parties are more free to choose among the available analysis packages. In all cases, this Guidebook strongly recommends that a single series of capacity and infra- structure analyses are performed using the selected analysis package. Both host and tenant should collaborate on specifying analysis inputs and in reviewing and interpreting results. Step 2. Identify Passenger Rail Agency Analysis Team and Agree on Modeling Procedures The passenger rail agency must enter discussions with a host railroad on capacity and infrastruc- ture investments with adequate technical support. Most important, the agency's team must include an individual with experience with the specific operations simulation software selected for capacity analysis. In many cases, the analysis will be carried out using the host railroad's software and corri- dor infrastructure input data. To ensure the passenger rail agency's interests are fully represented in the negotiations, model inputs and results must be subject to a knowledgeable independent review. When implementing passenger service on a major freight railroad, the most widely recom- mended approach to performing evaluations of a proposed passenger service is for the railroad and passenger rail agency to agree that one party (the freight railroad, the passenger rail agency, or a mutually acceptable consultant) will perform the analysis and share inputs and results with both parties. According to reports, some railroads have insisted on doing the calculations themselves and have been reluctant to share some details of inputs and results. This reluctance may be because of concern about revealing confidential business information or caution about getting involved in a lengthy dispute about the validity of input assumptions or interpretation of results. However, as confidence has grown in cooperative analysis and with the use of confidentiality agreements, these concerns have faded. Stakeholders report that the modeling process is becoming much more open. Step 3. Agree on Key Rail Service Inputs Once the analysis package has been selected, the next step is to define the passenger and freight rail services that will operate over the corridor. The typical data needed are discussed in the following paragraphs. Passenger Service. The service data needed for either intercity or commuter service or both will include: Target trip time, with station stops as planned. Both trip time without delays and a practical schedule time with an allowance or padding for delays should be defined. Adding excessive padding (such as exceeding 5 minutes per hour) to cover for poor operations or maintenance procedures should be avoided. Station locations and expected station stop dwell times. Train departure times and the number of daily trips in each direction. Service quality parameters, primarily OTP at final and intermediate stations, and fraction of trips missed due to equipment or infrastructure problems.

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Analysis and Modeling 39 If the service is to be developed in stages, this information is required for each develop- ment stage. Freight Service. The service data needed for freight service includes the numbers and types of trains forecast to move over the corridor corresponding to each passenger service develop- ment stage. Numbers of trains will be based on the railroads' business plans and economic fore- casts. Arrival times of trains approaching the corridor should be based on the freight railroad's operations plans, with a measure of the variability of arrival times. Some trains will follow pre- dictable schedules, for example, intermodal trains and regular local freight trains, while some may be seasonal, such as grain trains that run during harvest seasons. Some trains will run com- pletely at random. Day-of-week variations are also typical in freight service. It is advisable for the passenger rail agency to review the freight traffic forecasts independently, and raise questions if these appear to be inconsistent with state rail plans, likely local and national economic condi- tions, and announced plans to change freight train routing. Step 4. Carry out the Analyses The analyses will be tailored to each specific passenger rail situation. However, a typical set of analysis sequences might include: TPC-only analysis for passenger train trips to establish minimum track upgrades and speed increases to achieve the desired trip time, after allowing for reasonable schedule pad. Analyses of present-day freight and passenger (if any) operations on the corridor to check that the analysis adequately represents the real world and also to establish a baseline for the cur- rent performance of trains using the corridor. In particular, current delay statistics on the cor- ridor will set a target for corridor operations with added passenger trains. Further sets of simulations analyses with corridor speed upgrades determined using the TPC, and various capacity investments (double track, passing sidings, train control systems) to identify improvements that meet both capacity and performance goals. Delay statistics are the primary measure of performance; the corridor must maintain at least present freight train per- formance levels while meeting passenger train targets. This analysis is repeated for each stage in passenger service development if a multi-stage program is planned. Joint review of each analysis by the passenger rail agency and the host railroad, and discussion and resolution of any questions. Case Studies 4 provides an example of ongoing use of simulation modeling (in this case using RTC models) by the Capitol Corridor Joint Powers Authority (CCJPA) in California to manage track and service improvements on this corridor. CASE STUDIES 4 Application of the Rail Traffic Control Model and Capital Planning The CCJPA and its host railroad, the Union Pacific (UP), make extensive use of the RTC model for ongoing planning of capital investments. Full details of the route and passenger and freight services are coded into the model. CCJPA develops a long-term "Vision Plan" for the corridor and communicates this to UP. UP then runs the RTC model and develops plans for investments needed to accommodate each increment of passenger rail service, especially identifying bottlenecks that would constrain future freight service growth and journey time reductions. UP also develops cost estimates for the proposed improvements so that, after review and negotiations, CCJPA can issue a work order under the master agreement to execute the work as funding becomes available.