No abstract

No abstract

Traditional transit systems are usually composed of fixed routes and stops, which are suitable in densely populated areas. This paper presents a reformulation of the flexible transit model developed by Nourbakhsh and Ouyang (2012) to adapt it to many low demand cities in the world, especially those characterized by radial street patterns. Unlike traditional ones, buses of the proposed transit network are allowed to traverse in a predetermined service area and their precise trajectories hinge on the exact locations of passengers. To identify the optimal topology structure of the flexible transit system, continuous approximation approaches are developed to explore the optimal value of design parameters of the whole system, defining the optimal network layout through minimizing its objective function. To exhibit its advantages, numerical experiments are conducted to compare the flexible transit system with its two variants. The results show that the flexible transit system proposed in this paper outperforms the other two variants. The higher the access cost is, the more it would tilt towards the flexible transit system with a significant margin. Besides, the flexible transit system in a radial pattern competes more effectively than that in a grid structure. This is encouraging because the proposed transit system can be applied in a number of real-world cases.

In order to develop a program to calculate indexes in high-speed train CRH running process on passenger dedicated railway such as train's running time, the maximum speed, and energy consumption and so on, an automatic constant speed train traction calculation model and algorithm is built by the paper. The CRH train operation process is divided into four parts: the start and traction accelerate process, constant speed traction process, speed regulation braking process and pull-into and brake process. Each calculation algorithm is established respectively for each process. Finally, the models and algorithms are tested and compared with non-constant speed traction calculation model. The test demonstrates that the model and algorithms are effective. INTRODUCTIONCRH train traction calculations can calculate train's running time, the maximum speed, and energy consumption and so on. It can also estimate operation capacity when a train is faulty, analyze design parameters of lines and signal, optimize transport organization. The current traction calculation study rarely considers the differences of train operation control among high-speed railway. The universal traction calculation algorithm was not accurate enough. Therefore, design an automatic constant speed traction calculation model and algorithm adapted to the characteristics of CRH train operation control has important significance.