scholarly journals Exploring Benefits of Using Blending Splines as Transition Curves

2020 ◽  
Vol 10 (12) ◽  
pp. 4226
Author(s):  
Tanita Fossli Brustad ◽  
Rune Dalmo
Keyword(s):  
High Speed ◽  
Transition Curve ◽  
End Points ◽  
Circular Arc ◽  
Track Geometry ◽  
Railway Construction ◽  
Spline Curves ◽  
High Speed Trains ◽  
Transition Curves

Track geometry is a fundamental subject in railway construction. With the demand for increased capacity in terms of load and speed, the need for suitable transitions between consecutive track sections is highly relevant. Properly constructed transition curves lead to improved travel comfort, increased safety, and reduced wear. The well known clothoid curve is widely used as a transition curve; however, the linear curvature is not sufficiently smooth to meet the requirements for railways carrying high speed trains or heavy hauls. Blending spline curves are flexible spline constructions possessing favourable smoothness properties at the end points, which makes them considerable for use as transition curves. This paper demonstrates some selected blending splines applied as transition curves between two existing circular arc segments selected from the Ofotbanen railway. The main results in this paper are related to the smoothness at the end points and the behaviour of the curvature of the curves, where the new transition curves were shown to be smoother than the original clothoid. Another new result is the observation that the proposed method allows for the improvement of existing railways without forcing extensive changes to the original track. Some representative examples are included to highlight the flexibility of this first instance of blending splines as transition curves.

scholarly journals Modelling of the shape of railway transition curves from the point of view of passenger comfort

2021 ◽  
Vol 60 (4) ◽  
pp. 205-217
Author(s):  
Krzysztof Zboiński ◽  
Piotr Woźnica ◽  
Yaroslav Bolzhelarskyi
Keyword(s):  
High Speed ◽  
Point Of View ◽  
Transition Curve ◽  
Optimum Shape ◽  
Railway Vehicle ◽  
Vehicle Model ◽  
Circular Arc ◽  
Passenger Comfort ◽  
Rail Vehicle ◽  
Transition Curves

In the past, railway transition curves were not used. Instead of it, a simple connection of the straight track and circular arc was applied. Nowadays, such simplicity is not allowed due to the increasing vehicle operating velocities. It is mainly visible in the high-speed train lines, where long curves are used. The article aims to develop a new shape of railway transition curves for which passenger travel comfort will be as high as possible. Considerations in this paper concern the polynomials of 9th- and 11th-degrees, which were adopted to the mathematical model of the mentioned shape of curves. The study's authors applied a 2-axle rail vehicle model combined with mathematically understood optimisation methods. The advanced vehicle model can better assign the dynamical properties of railway transition curves to freight and passenger vehicles. The mentioned model was adopted to simulate rail vehicle movement in both cases of the shape of transition curves and the shape of circular arc (for comparison of the results). Passenger comfort, described by European Standard EN 12299, was used as the assessment criterion. The work showed that the method using the 2-axle railway vehicle model combined with mathematically understood optimisation works correctly, and the optimisation of the transition curve shape is possible. The current study showed that the 3rd-degree parabola (the shape of the curve traditionally used in railway engineering) is not always the optimum shape. In many cases (especially for the long curves), the optimum shape of curves is between the standard transition curves and the linear curvature of the 3rd-degree parabola. The new shapes of the railway transition curves obtained when the passenger comfort is taken into account result in new railway transition curves shapes. In the authors' opinion, the results presented in the current work are a novelty in optimisation and the properties assessment of railway transition curves.

On the Planning and Construction of Railway Curved Track

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Sono Bhardawaj ◽  
Rakesh Chandmal Sharma ◽  
Sunil Kumar Sharma ◽  
Neeraj Sharma
Keyword(s):  
High Speed ◽  
Time Derivative ◽  
Railway Track ◽  
Lateral Acceleration ◽  
Transition Curve ◽  
Railway Vehicle ◽  
Geometric Conditions ◽  
Curve Track ◽  
Curved Track ◽  
Transition Curves

Increasing demand for railway vehicle speed has pushed the railway track designers to develop high-quality track. An important measure of track quality is the character of the transition curve track connecting different intersecting straight tracks. A good transition curve track must be able to negotiate the intermittent stresses and dynamic effects caused by changes in lateral acceleration at high speed. This paper presents the constructional methods for planning transition curves considering the dynamics of movement. These methods consider the non-compensated lateral acceleration, deviation in lateral acceleration and its higher time derivatives. This paper discusses the laying methods of circular, vertical and transition curves. Key aspects in laying a curved track e.g. widening of gauge on curves are discussed in this paper. This paper also suggests a transition curve which is effective not only from a dynamic point of view considering lateral acceleration and its higher time derivative but also consider the geometric conditions along with the required deflection angle.

scholarly journals Determination of Necessary Subsidiary Track According to Train Operation Frequency in a Heterogeneous Train Pattern

2020 ◽  
Vol 10 (12) ◽  
pp. 4164
Author(s):  
Hyoung June Kim
Keyword(s):  
Genetic Algorithm ◽  
Waiting Time ◽  
High Speed ◽  
The Third ◽  
Railway Construction ◽  
Different Types ◽  
High Speed Trains ◽  
Train Operation ◽  
Operation Frequency

In this study, a genetic algorithm was used to calculate the scheduled waiting time according to the train operation frequency of heterogeneous trains operating on one track. The acquired data were then used to determine the appropriate subsidiary track at which high-speed trains can load or release cargo away from low-speed trains. A metaheuristic genetic algorithm was applied and implemented using Javascript/jQuery. Six cases were investigated, which provided values of subsidiary track that vary according to the operation frequencies of different types of trains, and solutions were derived through 100 simulations using a stochastic method. The analysis results showed that the train overtaking frequency was the highest at the third intermediate station within the simulation, suggesting that this particular station requires a subsidiary track, even if the operating frequency of each train differs across the entire track considered in this study. The results of this study are expected to facilitate objective and practical planning during railway construction.

scholarly journals Optimum Railway Transition Curves—Method of the Assessment and Results

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3995
Author(s):  
Krzysztof Zboinski ◽  
Piotr Woznica
Keyword(s):  
Optimization Methods ◽  
Transition Curve ◽  
Vehicle Model ◽  
Circular Arc ◽  
Passenger Comfort ◽  
Rail Vehicle ◽  
Railway Engineering ◽  
Transition Curves ◽  
Vehicle Movement

This article discusses the optimization of railway transition curves, through the application of polynomials of 9th and 11th degrees. In this work, the authors use a 2-axle rail vehicle model combined with mathematically understood optimization methods. This model is used to simulate rail vehicle movement negotiating both a transition curve and circular arc. Passenger comfort is applied as the criterion to assess which transition is actually is the best one. The 4-axle vehicle was also used to verify the results obtained using the 2-axle vehicle. Our results show that the traditionally used in a railway engineering transition—3rd degree parabola—which is not always the optimum curve. This fact is especially valid for the longest curves, with lengths greater than 150 m. For such cases, the transition curves similar to standard curves of 9th and 11th degrees is the optimum ones. This result is confirmed by the use of the 4-axle vehicle.

scholarly journals Effect of train speed and track geometry on the ride comfort in high-speed railways based on ISO 2631-1

2019 ◽  
Vol 234 (7) ◽  
pp. 765-778
Author(s):  
Chi Liu ◽  
David Thompson ◽  
Michael J Griffin ◽  
Mani Entezami
Keyword(s):  
High Speed ◽  
Dynamic Models ◽  
Ride Comfort ◽  
Railway Vehicle ◽  
Track Geometry ◽  
Car Body ◽  
Flexible Mode ◽  
High Speed Trains ◽  
All Speeds ◽  
Iso 2631

The operational speeds of passenger trains have been increasing and now often exceed 300 km/h. Higher speeds can lead to increased vibration and reduced ride comfort for railway passengers. This study investigates the combined effect of speed and track geometry on vibration discomfort in high-speed trains. Railway vehicle dynamic models with various levels of complexity are used, with the measured geometry of a section of a high-speed track as an input. The models have been calibrated with vibration measurements carried out in a train running over this section of the track and then applied to predict the vibration discomfort at increased speeds. To evaluate the vibration discomfort at speeds up to 400 km/h, information on track geometry should include wavelengths up to at least 150 m. Vertical irregularities have the greatest effect at all speeds but lateral irregularities are also important. Both the vertical and lateral irregularities of a high-speed track should be controlled at wavelengths of 50–100 m that excite rigid modes of the car body, corresponding to frequencies of typically 1–2 Hz. Additionally, vertical irregularities with wavelengths of 5–12 m that excite the fundamental flexible mode of the car body, typically around 10–15 Hz, should also be controlled. The effects of cant, the rates of change of cant, and the radius of vertical curves are also evaluated although they only have a small effect on vibration discomfort.

scholarly journals Improvement of Characteristics of the Railway Direction Kharkiv-Dnipro with the Purpose of Introducing the high-speed Passenger Traffic

2019 ◽  
Vol 67 ◽  
pp. 02004
Author(s):  
Maksym Kutsenko ◽  
Sergii Zmii ◽  
Oleksandr Rozsokha ◽  
Ganna Shapoval ◽  
Olga Semenova
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Rail Transport ◽  
Small Radius ◽  
High Speed Rail ◽  
Passenger Traffic ◽  
High Speed Trains ◽  
Service Sectors ◽  
Circular Curves ◽  
Transition Curves

The high efficiency of high-speed rail transport contributes to its development both in the service sectors and in the construction of devices for servicing high-speed trains, in particular, track development. At the same time, it is necessary to take into account the obvious problems that accompany the process of reconstruction of railways during the transition to high-speed passenger traffic. Among them, the presence of small radii of circular curves, an insufficient length of straight inserts and transition curves should be noted. In this paper, it is proposed to consider small-radius curves located close to each other as one common module when reconstructing railways with the aim of introducing high-speed passenger traffic. The implementation of this approach will allow solving one of the main problems - straightening of the railway section. This will increase the speed of passenger trains and reduce travel time by reducing the length of the route. The article deals with the task of reconstruction of modules consisting of three adjacent curves, which occur when improving the characteristics of the plan of the Kharkiv-Dnipro railway direction.

Chains and Arteries: Railways as Visual Propaganda during the Second Sino-Japanese War

2020 ◽  
Vol 2 (1) ◽  
pp. 57-96
Author(s):  
WU Xueshan
Keyword(s):  
Technological Progress ◽  
High Speed ◽  
Large Scale ◽  
Chinese Government ◽  
Power Relationships ◽  
Visual Narratives ◽  
Railway Construction ◽  
Social Governance ◽  
High Speed Trains ◽  
The Times

From the time of their invasion in 1931, the Japanese commenced railway construction in China on a large scale, not only to transport troops and supplies, but, just as importantly, to verify Japan’s achievements in “constructing” a new East Asia. To this end, Japanese and Manchurian propaganda images were replete with high-speed trains, as epitomes of the technological progress of the times. Conversely, a primary military goal of the Chinese government was the destruction of these very railroads. Thus, a variety of photographs and woodcut prints of the period depict scenes of Chinese combatants and civilians cooperating to destroy Japanese railways and trains, which were taken to represent the Japanese invader’s machinery of violence. In this context, railroads and other implements of modernity were implicated by war, and both sides were fully cognizant of the capacity of railroads to conquer space. The battle over the sovereignty of these railways, then, whether to build or destroy them, signified an expansion of military and political power. Focusing on the different ways in which railroads were represented in this conflict, this paper explores how different visual narratives pointed to power relationships of the time, either to validate or subvert existing social governance.

scholarly journals Smoothed transition curve for railways

2019 ◽  
Vol 2019 (7) ◽  
pp. 19-31 ◽  
Author(s):  
Władysław Koc
Keyword(s):  
Final Section ◽  
Initial Section ◽  
Point Of View ◽  
Smooth Transition ◽  
Railway Track ◽  
Transition Curve ◽  
Practical Implementation ◽  
Circular Arc ◽  
New Form ◽  
Transition Curves

The work draws attention to the existing situation in the area of transition curves used in the geometric layouts of the railway track. Difficulties in the practical implementation and maintenance of very small horizontal ordinates of the transition curve and the ordinates of the gradient due to cant in the initial section, appearing on smooth transition curves, were indicated. The main reason for this situation was the excessive smoothing of the curvature in their initial section. Employing the method of curvature identification by differential equations, a new form of the curve was obtained, which was referred to as the "smoothed transition curve". A definite advantage of this curve was shown, from the implementation point of view, over representing the smooth transition curves of the Bloss curve. . It seems that it could successfully compete with the commonly used clothoid, to which it is similar in the initial section, while it differs significantly along its further length, especially in the final section, where it provides a gentle entry from the transition curve into a circular arc.

Railway transition curves and the large circular arc radii

2018 ◽  
Vol 121 ◽  
pp. 423-430
Author(s):  
Piotr Woźnica ◽  
Krzysztof Zboiński
Keyword(s):  
Vehicle Body ◽  
Transition Curve ◽  
Optimum Shape ◽  
Function Evaluation ◽  
Vehicle Model ◽  
Mathematical Methods ◽  
Circular Arc ◽  
Vertical Accelerations ◽  
Optimization And Simulation ◽  
Transition Curves

This work concerns the search for the optimum shape of railway transition curves (TCs). In work the authors used mathematical methods of optimization and simulation. The computer simulation concerned the dynamic behavior of the the 2-axle rail vehicle model. As the transition curve the authors adopted a polynomial of degree n, where n=9 and 11. The quality function (evaluation criterion) used concerned vertical accelerations of the vehicle body. The authors used large circular arc radii – R=3000 m and 4000 m. The aim of the research was to find the optimum shapes of the TCs, taking into account the criterion adopted and comparison of them among themselves.

Sign in / Sign up

Export Citation Format

Share Document