1. Slide 1 ILLINOIS - RailTEC Capacity of Single-Track Railway Lines with Short Sidings to Support Operation of Long Freight Trains Ivan Atanassov, C. Tyler Dick, Christopher P.L. Barkan Rail Transportation and Engineering Center University of Illinois at Urbana-Champaign 2014

2. Slide 2 ILLINOIS - RailTEC Research Problem  The North American railroad network is projected to experience increased demand for freight transportation in the coming decades  Use of distributed power locomotives in heavy-haul service has allowed for greater efficiencies through operation of longer freight trains  The majority of national mainline routes are single track; as a result, the potential economic and operational advantages offered by long trains are constrained by the inadequate length of many existing passing sidings  Characterize the interaction between lengths of passing sidings and trains, and the subsequent effect on track utilization and train delay

3. Slide 3 ILLINOIS - RailTEC Rail Traffic Controller  Rail Traffic Controller (RTC) is the industry-leading rail traffic simulation software in the United States, and is used by a wide range of public and private organizations, including most Class I railroads, Amtrak, and Bay Area Rapid Transit (BART). Input  Track layout  Signals  Switches  Speed limit  Train consist Output  Train delay  Dwell  Siding usage counts  Train performance calculator  Time-space diagram

4. Slide 4 ILLINOIS - RailTEC Simulated Route and Freight Train Characteristics Route Characteristics Values Length 240mi. Siding Spacing 10mi. Total No. of Sidings 23 Siding Lengths 1.25mi. (short), 2mi. (long) Traffic Composition 100% Freight Locomotives SD70 (x2 or x3) No. of Cars 100 (short train), 150 (long train) Total Length of Cars 5,500ft. (short train), 8,250ft. (long train) Max. Freight Speed 50mph (45mph through siding) Traffic Control System 2-block, 3-aspect CTC

5. Slide 5 ILLINOIS - RailTEC Experiment Design Factors and Levels Experiment Design Factors No. of LevelsLevel Specification Percent Long Sidings 14 0, 4, 9, 13, 22, 30, 48, 52, 70, 78, 87, 91, 96, 100 Percent Long Trains 40, 25, 50, 75 Directional Distribution 2 50-50 (bi-directional), 100-0 (uni-directional) Freight Throughput 23,600 cars & 2,400 cars

6. Slide 6 ILLINOIS - RailTEC Examples of Balanced Long Siding Distributions

7. Slide 7 ILLINOIS - RailTEC Delay as a Function of Percent Long Sidings  To operate with a high percentage of long trains, only half of the sidings on a route need to be extended in order to maintain the baseline level of service

8. Slide 8 ILLINOIS - RailTEC Delay Variance as a Function of Percent Long Sidings  Simulated delay values become relatively consistent when the route has at least 20 percent long sidings

9. Slide 9 ILLINOIS - RailTEC Uni-Directional Long Trains  Long train operations that are fully uni-directional have no significant delay impact; an uneven directional distribution of long trains, however, produces a familiar delay trend 3,600-Car Throughput

10. Slide 10 ILLINOIS - RailTEC Influence of Long-Train Directional Preference  The case with long train directional preference follows the same delay patterns as those for the even, bi-directional cases, converging again to a point at roughly 50 percent long sidings 3,600-Car Throughput

11. Slide 11 ILLINOIS - RailTEC Future Directions  Investigate a broader range of freight throughput values to determine the consistency of the free-flow point of 50 percent long sidings  Investigate train and siding length relationships on routes with uneven siding spacing  Introduce heterogeneity in the form of passenger trains to the simulations  Extend the issue of long trains to yard & terminal requirements, and the subsequent interaction with mainlines  Train length extension of analytical Optimal Siding Location Model

12. Slide 12 ILLINOIS - RailTEC Acknowledgments Technical collaboration and assistance from: Mei-Cheng Shih, Taşkın Şehitoğlu, Samuel Sogin, Xiazhi Zhang This research supported by: National University Rail Center (NURail) a USDOT-OST Tier 1 University Transportation Center

13. Slide 13 ILLINOIS - RailTEC Thank You Ivan Atanassov Graduate Research Assistant Rail Transportation and Engineering Center (RailTEC) University of Illinois at Urbana-Champaign E-mail: atanass1@illinois.edu