Capacity Analysis on Single and Double-Truck Lines
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Date
2014-07
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Publisher
AAU
Abstract
Railway networks are complex technical systems. Investments in railway infrastructure are
expensive and already constructed railway infrastructure is not easily adjusted or changed.
Dimensioning and constructing railway lines and networks therefore require extensive
knowledge of future operation and demand. However, experience shows that the traffic often
develops differently than expected. This means that railway infrastructure has to be designed for
flexibility, i.e. for different operational conditions. To achieve such flexibility, a deep knowledge
of infrastructure, timetable and perturbation properties, as well as inter-correlations between
these, is essential.
This research has been investigate the impact of various operational changes on different level of
heterogeneity to specify the potential use of operational changes to reduce delay in different scenarios
especially for single- and double-track systems based on graphical calculation from time-space
diagram and CN parametric model. The time-space diagram which is a simple but powerful
graphical thinking tool has been used to mode the idealized existing operation. CN parametric
model was used to investigate the impact of various operational changes on differing levels of
heterogeneity on a hypothetical signalized, single-track rail line using delay as capacity metric
unit. Changes considered included: adding sidings, increase in train headway, equalizing
maximum speeds, increasing uniformity, removing dispatching priorities and the combination of
the best ones.
Since the railway transportation can have significant effects on mobility, economic development,
environmental quality, government finance and the quality of life, this study did analyze that the
change of each parameters would have great improvement for the idealized existing operation,
the combination of specified alternatives, specially adding sidings did provide a great capacity
increment for the particular subdivisions. Those results from this study has great significance for
railway operational capacity problems specifically for single -track lines and provides insight
into which aspects of train type heterogeneity have the greatest impact on delay and leads to
investigate the potential use of different operational changes that may reduce this delay in
Ethiopian, Addis Ababa-Djibouti rail line.
Description
Keywords
Double-Truck Lines, Single-Truck Lines, Capacity