Addis Ababa Light Rail Transit Signaling System Design Analysis
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Date
2014-08
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Addis Ababa University
Abstract
The Signal System, which includes the functions of signal protection, grade crossing protection, and traffic signal coordination, shall be designed to allow light rail transit vehicles to meet the required line capacity, while providing a safe and operationally flexible system. Light rail shall operate in dedicated right-of-way or share the street with existing traffic. The dedicated portions of right-of-way shall use conventional fixed color light signals for train separation and safe braking distance.
In view of that, in this thesis work the existing Addis Ababa LRT signaling system is analyzed. Strong sides and limitation of the existing design are discussed. And it is found that the signaling design on the line constructed ground has limitations according to safety, operational efficiency and other factors which are discussed well. Afterwards different design approaches will be presented and CTCS level 0 is chosen according to parameters stated. Therefore, on this section the design will be made to implement Automatic Block Signaling, wayside signals and cab signaling systems.
Then braking distance of each stations are calculated so as the wayside signals are placed on safe locations. In order to calculate the operational efficiency the headway time between trains calculated. The speed limit of all necessary curves, switches and turnout are calculated and the average speed of the system is obtained.
Finally the new design versus the existing design is compared based on safety, operational efficiency, cost, energy consumption and passenger satisfaction issues. And it is found that the new design improve headway time by 63.84% and improves the average speed by 63.97% that leads the system with new design is more efficient than the existing design.
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Keywords
CTCS, AFBS, Breaking distances, Headway time