Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations (2014) / Chapter Skim
Currently Skimming:
Pages 40-67
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 40... ...
40 C H A P T E R 4 4.1 Introduction Presented herein are three case studies that illustrate various capacity assessment methodologies to determine if adequate line capacity exists given specific assumptions about the train mix, volume, and operating patterns. The first case study, a conceptual grid time analysis of the LOSSAN Corridor in Southern California, served as a means to help public agencies along the corridor understand the range of capacity enhancements required over time to ensure fluid passenger and freight operations.
|
From page 41... ...
Best Practices 41 4.2.2 Existing Corridor Services There are four different corridor passenger rail services. These are: • The Pacific Surfliner, operated by Amtrak with financial support from Caltrans Division of Rail, between San Diego and San Luis Obispo via Los Angeles Union Station (LAUS)
|
From page 42... ...
42 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations Figure 4-1. Line densities on LOSSAN corridor segments in 2008.
|
From page 43... ...
Best Practices 43 • With 15 minutes between sidings, maximum capacity equals four trains per hour between sidings. • Maximum daily capacity or theoretical capacity equals four trains per hour multiplied by 24 hours or 96 trains per day.
|
From page 44... ...
44 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations will be greater than the estimated practical capacities of the segments, indicating that capacity enhancements for these line segments will be needed at some point. Train volumes for the intervening years were calculated (these were not shown in the table for the sake of simplicity)
|
From page 45... ...
Best Practices 45 Over the intervening years, conditions on the corridor have changed in numerous ways. Freight train growth, for one thing, has been slower than anticipated, an outcome of the recent economic recession and curbing of rail-borne international container volume going to and from the Ports of Los Angeles and Long Beach.
|
From page 46... ...
46 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations A key element of all work phases since the beginning of the project was the use of rail operations simulation to identify line capacity enhancements required to ensure fluid passenger and freight rail operations on the line, which is also a federally designated high speed rail corridor. The simulation task was performed by means of the Rail Traffic Controller software, which is a standard tool for rail operations analysis and train performance evaluation.
|
From page 47... ...
Best Practices 47 variations to scheduled dwell times and initial departure times were applied to simulate the effect of minor random day-to-day impacts on train operations. The results were averaged over the runs and are presented below.
|
From page 48... ...
48 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations added to the TPC schedule to account for a number of factors. For a double track network the schedule pad is calculated by increasing the train runtime by a minimum of 7% to take into account such factors as human operation instead of perfect TPC operation, temporary slow orders, congestion or off-schedule trains, adverse weather conditions, and signal imposed delay, etc.
|
From page 49... ...
Best Practices 49 4.3.4 Simulation Results Due to the increase in freight train length and weight, the performance parameters do show a slight degradation of operating performance when evaluating 2030 No Build versus the 2011 No Build Case. The delay statistics for 2016 V2d (2030 Build)
|
From page 50... ...
50 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations quality. Optimization of the freight service can potentially provide further reductions in delay for both passenger and freight service.
|
From page 51... ...
Best Practices 51 This question was first explored in a 2008 analysis. The 2010 study was an update.
|
From page 52... ...
52 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations perform the simulation.) The 2010 study took into account the then current Sounder, Amtrak Empire Builder and Cascade trains, plus a third Cascade round trip between Seattle and Vancouver, British Columbia.
|
From page 53... ...
Best Practices 53 4.4.2.2 Network Simulations The rail network for the simulations was drawn using current BNSF track charts and time tables (variously dated between 2007 and 2010) , provided by BNSF simulation modelers.
|
From page 54... ...
54 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations Improvements in the vicinity of Delta Yard, identified and modeled during the previous study, were not included in the 2010 effort. Specifically: • Ease of main line curve at north end of the yard • New main line around the yard • Revision of yard tracks/leads However, by means of distance equations, study modelers coded longer receiving and departure tracks at Delta Yard to avoid long freight trains blocking yard approaches during crew change layovers or switching operations.
|
From page 55... ...
Best Practices 55 Improvement Simulaon 1 Simulaon 2 Simulaon 3 Simulaon 4 Freight Service Current Service Current Service Current Service Current Service Cascade Service and Amtrak Empire Builder 2 Vancou'r RT 1 Em.
|
From page 56... ...
56 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations do not significantly influence passenger trains' average speed, which stays consistent at about 36 miles per hour. The average speed of expedited freight trains (those with highest operating priority)
|
From page 57... ...
Best Practices 57 The reader should note two context elements for the grid analysis described below: • Grid time analysis would most naturally be the first and simplest scoping-level evaluation of service capacity for a rail corridor. For purposes of illustration the guidebook team chose an alignment that had earlier been modeled in RTC so that readers would be able to compare the products of each approach.
|
From page 58... ...
58 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations GRID BREAKDOWN Blaine - Evere Rail Corridor Siding length (feet) Siding Name Milepost (miles)
|
From page 59... ...
Best Practices 59 The single track grid lengths range from approximately two miles in distance to as much as 13 miles. The longer the distance of each grid segment, the less capacity that the system is capable of handling.
|
From page 60... ...
60 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations GRID BREAKDOWN Blaine - Evere Rail Corridor Siding Name Single Track Grid Lengths between Sidings (Miles) Total Time for Each Train to Cross Grid Including Border Delays (Minutes)
|
From page 61... ...
Best Practices 61 Table 4-12. Impact of existing passenger trains.
|
From page 62... ...
62 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations In general, whenever the calculated capacity and the actual capacity numbers are relatively close to one another, a potential area of conflict is identified. In this case, it is simply a "flag" that is raised when there is an introduction of the new passenger services.
|
From page 63... ...
Best Practices 63 MP 106.37 (south switch of Ferndale siding) and MP 83.53 (north switch of new Samish/Bow siding)
|
From page 64... ...
64 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations was contemplated. However, the analysis did identify the area most in need of further study and set a path for subsequent evaluation with more sophisticated analytical tools.
|
From page 65... ...
Best Practices 65 speed limit) of the segments can be modified by clicking the segment and choosing edit speed limit pop-up.
|
From page 66... ...
66 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations As shown in the table, Simulation 3 results (average speed and average delay) for freight trains were better than the Simulation 1 (base case)
|
From page 67... ...
Best Practices 67 a flag over potential service issues, which both the RTC and the SU Tool confirmed: passenger train performance suffers. It is worth noting that grid time analysis can be used to quickly identify potential solutions for capacity constraints and test them -- albeit not as definitively as either of the two simulation methodologies.
|
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.