Analyzing the Progression From Single to Double Track Networks

Abstract

Long term demand for rail transportation in North America is projected to increase considerably in the coming decades. A significant portion of the routes in the United States are single track with passing sidings. Eventually, the second mainline track will become necessary to maintain network fluidity. However, the full funding for the second track may not be available all at once; subsequently the track can be phased in over time creating a hybrid track configuration. Depending upon the traffic characteristics, traffic will transition from a delay characteristic of single track to a delay characteristic of double track. A response surface model was developed that tested various factors including the amount of second main track added, traffic volume, traffic composition, and the speed differential between train types. Design of experiments software (JMP) was used in conjunction with railway simulation software (Rail Traffic Controller) to conduct the analysis. The benefit of full double track can be realized for high priority trains with partial double-track. However, the low priority traffic may not experience double-track-like performance until nearly the entire second mainline track is installed. The results suggest a linear relationship between miles of second mainline track added and reduction in train delay. The maximum speed of the freight train has a great impact on train delays in a congested network. These results further the understandings of key mainline interactions between passenger and freight trains. In addition the models presented will facilitate the development of an optimal incremental upgrade model for capacity expansion. Also, the methodology presented can be adopted to analyze the progression from double to triple track.

Comprehensive Evaluation of Operating Speeds for High-Speed Railway: A Case Study of China High-Speed Railway

“…A typical feature of the CHSR operating plan is the mixed traffic within the same track line [26,27], which produces the speed heterogeneity in CHSR network [28]. Speed heterogeneity brought about by mixed train operations is an important issue on shared-use rail corridors [29][30][31].…”

Sensitivity of Freight and Passenger Rail Fuel Efficiency to Infrastructure, Equipment, and Operating Factors

“…After a regression model has been constructed for each experiment, the sensitivity of the response (fuel efficiency) to changes in the inputs (the factors listed in Table 1) can be quantified by the arc elasticity method, as described by Allen and Lerner (24). This approach has been used in similar research investigating the influence of various factors on train delay (25). The arc elasticity method quantifies how fuel efficiency responds to normalized unit changes in each factor with respect to a base case.…”

Integrated Modeling of High Performance Passenger and Freight Train Planning on Shared-Use Corridors in the US

“…Speed heterogeneity brought by mixed train operations is an important issue on shared-use rail corridors (Dingler et al, 2009;Dingler, 2010;Sogin et al, 2013). In this subsection we fix passenger train speed but vary the speed of freight trains by a wide range from 12 mph to 120 mph.…”