A simplified approach to determine the optimum operating speed on high-speed railway lines

2009 ◽  
Vol 36 (2) ◽  
pp. 196-208
Author(s):  
Zübeyde Öztürk ◽  
Turgut Öztürk

In this study, cost–speed relationship for high speed railways was examined and optimum economic speed was investigated. The Eskişehir–Ankara section of the İstanbul–Ankara railway line, which is still under construction, was taken as the sample. This section has been completed and test runs are being conducted. The new line is constructed parallel to the old railway line and the operation speeds and operation forms of the trains on this line are not yet finalized. It is not yet clear what the maximum operation speeds of the trains will be and whether the operation will be restricted to only high speed passenger trains or a combination of passenger and freight trains will be used. Therefore, cost changes associated with speed for both operations were examined in the study. The speed for the lowest cost was investigated for the benefit of the operating institute. The rail line is scheduled to begin operation in 2010, and as such demand estimation values for 2010 and unit cost values of Turkish State Railways (TCDD) were utilized. Only construction and operation costs were analyzed, societal costs were not included in the study. Several costs were formulated independent ofthe speed, whereas the majority of them were formulated and calculated based on speed. Finally, the contribution of each studied cost component, in the total cost, and variations in these costs and total cost for different speeds for both operation conditions were analyzed in this study. It was found that some cost components increased and some decreased as the speed increases. Total cost, which includes all the cost components studied, initially dropped off then rose up as the speed incrementally increases. Minimum cost occurred at 200 km/h in the case of operating with only passenger trains, while it occurred at the second speed level in combined operation (where passenger trains are at the speed of 200 km/h and freight trains are at the speed of 90 km/h).

2021 ◽  
Vol 7 (1) ◽  
pp. 167-173
Author(s):  
Kelvin Riupassa ◽  
Narizma Nova ◽  
Endah Lestari ◽  
Sri Juniarti Azis ◽  
Wahyu Sulistiadi

Background: An ambulance is a vehicle designed to be able to handle emergency patients, provide first aid and carry out intensive care while on the way to a referral hospital. Ambulance operations require a large amount of funds obtained from APBD funds through tariffs that were passed through the DKI Jakarta Governor Regulation five years ago. For this reason, a new tariff is required to adjust to current conditions. Objectives: The purpose of this study is to calculate the unit cost of ambulance services in DKI Jakarta to be a consideration in the tariff setting policy in DKI Jakarta province. Research Metodes: This study uses a quantitative descriptive approach to obtain information about the unit cost of the Jakarta ambulance production unit. The method used is the calculation of real cost using the basis of the causes of costs. This research was conducted at the DKI Jakarta Emergency Ambulance using secondary data on investment costs, operational costs and maintenance costs in 2018. Results: The total cost of emergency ambulance in 2018 is known that the proportion of three cost components, namely operational costs, is 76%, followed by investment costs of 20% and maintenance costs of 3%. The calculation of the total cost of medical evacuation using the double distribution method is Rp. 98,915,016,805.00 divided by the number of medical evacuations in 2018 of 37,564 activities, the unit cost of medical evacuation for the AGD of DKI Jakarta Health Office is Rp. 2,633,215.00 without subsidies. APBD costs, while if the subsidy component is included in the calculation, the unit cost for one trip to the AGD of the Health Office is Rp. 604,071.00. This is still far above the current tariff of Rp. 450.00, so the cost recovery rate (CRR) is still below. 100%. Conclusion: From the three cost components consisting of investment, operational and maintenance costs,the largest proportion was operational costs at 76%. The Cost Recovery Rate has not reached 100% so that the existing rates have not covered the costs incurred.   Keywords: ambulance; price fixing; unit cost


Author(s):  
K. A. Gumus ◽  
V. E. Gulal

In the past few decades, high-speed railways have become an important transportation system due to their high operational speed, and globally, the networks of these railways have been extended. In addition, there is ongoing work on the construction of new high-speed railways as well as improving existing lines to achieve the same operational speed. To contribute to high-speed railway works in Turkey, this study compared two high-speed railway lines; an existing conventional line, the design of which was improved, and a new high-speed line. The design of an existing conventional railway line was improved according to optimal geometric characteristics of high-speed railways and an alternative line was simulated. These two lines were evaluated on three different types of land in terms of the required volume of earthworks, engineering structures and total cost. The results show that the length of the conventional line was reduced after the improvement process; however, new engineering structures are needed. Furthermore, compared to the alternative line, the track length and total length of engineering structures required for the improvement of the existing line was shorter and the volume of required earthworks was less resulting in lower costs.


2019 ◽  
Vol 124 ◽  
pp. 9-17
Author(s):  
Marcin Chrzan

The article will present aspects related to the construction (modernization) of railway lines in Poland on the example of the modernized section of the railway line E20 Warsaw-Terespol. The purpose of the modernization of this line was to adjust its technical parameters to the EU standards and requirements of AGC (European Agreement on Main International Railway Lines) and AGTC (European Agreement on Main International Combined Transport Lines and Associated Facilities) agreements, which provide for a maximum permissible speed of 160 km/h for steam passenger trains and 120 km/h for freight trains, with a permissible axle load of 22.5 tons. It will present the previous results of measurements on selected sections and the original concept of rail measurements using ultrasonic defectoscopy and satellite navigation.


Author(s):  
Xuewu Zhang ◽  
Yansheng Gong ◽  
Chen Qiao ◽  
Wenfeng Jing

AbstractThis article mainly focuses on the most common types of high-speed railways malfunctions in overhead contact systems, namely, unstressed droppers, foreign-body invasions, and pole number-plate malfunctions, to establish a deep-network detection model. By fusing the feature maps of the shallow and deep layers in the pretraining network, global and local features of the malfunction area are combined to enhance the network's ability of identifying small objects. Further, in order to share the fully connected layers of the pretraining network and reduce the complexity of the model, Tucker tensor decomposition is used to extract features from the fused-feature map. The operation greatly reduces training time. Through the detection of images collected on the Lanxin railway line, experiments result show that the proposed multiview Faster R-CNN based on tensor decomposition had lower miss probability and higher detection accuracy for the three types faults. Compared with object-detection methods YOLOv3, SSD, and the original Faster R-CNN, the average miss probability of the improved Faster R-CNN model in this paper is decreased by 37.83%, 51.27%, and 43.79%, respectively, and average detection accuracy is increased by 3.6%, 9.75%, and 5.9%, respectively.


2021 ◽  
pp. 147592172110360
Author(s):  
Dongming Hou ◽  
Hongyuan Qi ◽  
Honglin Luo ◽  
Cuiping Wang ◽  
Jiangtian Yang

A wheel set bearing is an important supporting component of a high-speed train. Its quality and performance directly determine the overall safety of the train. Therefore, monitoring a wheel set bearing’s conditions for an early fault diagnosis is vital to ensure the safe operation of high-speed trains. However, the collected signals are often contaminated by environmental noise, transmission path, and signal attenuation because of the complexity of high-speed train systems and poor operation conditions, making it difficult to extract the early fault features of the wheel set bearing accurately. Vibration monitoring is most widely used for bearing fault diagnosis, with the acoustic emission (AE) technology emerging as a powerful tool. This article reports a comparison between vibration and AE technology in terms of their applicability for diagnosing naturally degraded wheel set bearings. In addition, a novel fault diagnosis method based on the optimized maximum second-order cyclostationarity blind deconvolution (CYCBD) and chirp Z-transform (CZT) is proposed to diagnose early composite fault defects in a wheel set bearing. The optimization CYCBD is adopted to enhance the fault-induced impact response and eliminate the interference of environmental noise, transmission path, and signal attenuation. CZT is used to improve the frequency resolution and match the fault features accurately under a limited data length condition. Moreover, the efficiency of the proposed method is verified by the simulated bearing signal and the real datasets. The results show that the proposed method is effective in the detection of wheel set bearing faults compared with the minimum entropy deconvolution (MED) and maximum correlated kurtosis deconvolution (MCKD) methods. This research is also the first to compare the effectiveness of applying AE and vibration technologies to diagnose a naturally degraded high-speed train bearing, particularly close to actual line operation conditions.


Author(s):  
Guan-Chung Ting ◽  
Kuang-Yuh Huang ◽  
Keng-Ning Chang

Bearings for high-speed rotors are the key component of dental handpieces. The friction induced by conventional ball bearings restricts its speed and reduces its efficiency. In order to significantly improve the efficiency of dental handpieces, a mini-type cartridge that integrates a turbine and a spindle with radial aerostatic bearings and axial passive magnetic bearings has been ingeniously designed and realized. Around the rotating spindle, there is a high-pressured air film built up by a pair of radial aerostatic bearings, and magnet rings are applied to create repulsive forces to axially support the rotating spindle. The high-pressured air film comes from the specifically designed separable orifice restrictors, which can be easily and precisely manufactured. Frictionless bearing effect can be achieved by aerostatic principle, and the magnetic principle is applied to create large repulsive force against the axial working force. A tri-directional air inlet is designed to reduce radial loading force of a spindle during working. The modularized form of the magneto-aerostatic bearing allows it to be easily assembled and replaced in the very compact space of a mini-type cartridge. Through analytical simulations with fluid-dynamics software (CFD) and experiments, the magneto-aerostatic bearing is optimized to bring out efficient performance in its limited space. The experiments have verified that its noise level is 15dB lower than the conventional cartridge with ball bearings, and its startup air pressure is reduced from 0.4 bar to 0.1 bar. Under the same operation conditions, the newly developed cartridge with magneto-aerostatic bearings creates twice higher speed than that of the conventional one.


2014 ◽  
Vol 716-717 ◽  
pp. 342-346
Author(s):  
Xiao Jun Zhou ◽  
Bo Jiang ◽  
Yue Feng Zhou ◽  
Yu Yu

On the basis of different landform and multifarious topography in rugged mountainous area in southwest China, typical tunnel portals for single track tunnels in a new high speed railway line have been presented in the paper. The portal comprises headwall, shed tunnel, bridge abutment and its support. Portal with headwall is suitable for tunnel to resist front earth pressure on high and abrupt slope. Shed tunnel is placed in front of headwall so as to prevent rockfall; its outward part is built into a flared one. Meanwhile, the installation of bridge and its abutment are also included in the portal according to landform in the paper.


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