Sample Applications of Transition Curves in Horizontal Alignment

2017 ◽  
pp. 89-107
Author(s):  
Andrzej Kobryń
Keyword(s):  
Horizontal Alignment ◽  
Transition Curves

Existing Railway Horizontal Alignment Reconstruction Algorithm Based on Line Segments Identification

2013 ◽  
Vol 405-408 ◽  
pp. 1772-1776 ◽  
Author(s):  
Wei Liu ◽  
Jian Hong Wang ◽  
Yang Li ◽  
Wei Li
Keyword(s):  
Least Square Method ◽  
Reconstruction Algorithm ◽  
Least Square ◽  
Engineering Practice ◽  
Line Segments ◽  
Horizontal Alignment ◽  
On Line ◽  
Abnormal Points ◽  
Transition Curves ◽  
Circular Curve

A Line Segments Identification model is put forward to realize the existing railway horizontal alignment reconstruction. Firstly, Hough transform based on constraint adjustment quantity is introduced to reject the abnormal points that will affect the quality of the identification in latter steps. Then total least square method is used to get the linear segments, after which the circular curve segments and the transition curves segments will be got. At last, an evaluation function which has four arguments: circular curve radius , two transition curves length and length of straight line between curves was built and its function value is the sum of squares of all distances from measuring points to reconstruction alignment, based on the function , optimal alignment will be solved out by Powell method. Example shows that the reconstruction result is considerably superior to the traditional method and is feasible for the engineering practice.

Traffic and speed characteristics on two-lane highways: field study

2003 ◽  
Vol 30 (6) ◽  
pp. 1042-1054 ◽  
Author(s):  
Yasser Hassan
Keyword(s):  
Light Condition ◽  
Operating Speed ◽  
Ambient Light ◽  
Horizontal Curve ◽  
Vehicle Class ◽  
Rural Highways ◽  
Horizontal Alignment ◽  
Heavy Truck ◽  
Traffic Composition ◽  
Rural Highway

Many models have been developed to evaluate the operating speeds on two-lane rural highways. However, provided information usually lacks details essential to assess their applicability at locations other than where they were developed. This paper presents a procedure to interpret raw data collected on three horizontal curve sites of different two-lane rural highway classes in Ontario. The speed observations were categorized into three vehicle classes (passenger car, light truck, and multi-axle heavy truck) and four light condition categories (day, night, and two transition periods). The minimum headway and percentile value to define the operating speed were examined, and a revision of the current practice deemed not warranted. The findings also indicated that operating speeds do not depend on the time or vehicle class. Finally, the horizontal alignment affects the operating speed, but the speeds of the two travel directions on a horizontal curve may differ even with little contribution of the vertical alignment.Key words: highway geometric design, operating speed, traffic composition, traffic counters, ambient light, acceleration, deceleration.

Stability of a Rigid Body With an Oscillating Particle: An Application of MACSYMA

1985 ◽  
Vol 52 (3) ◽  
pp. 686-692 ◽  
Author(s):  
L. A. Month ◽  
R. H. Rand
Keyword(s):  
Angular Velocity ◽  
Rigid Body ◽  
Classical Problem ◽  
Moment Of Inertia ◽  
Model Parameters ◽  
Stability Chart ◽  
The Stability ◽  
Transition Curves ◽  
Minimum Moment ◽  
Small Angular Velocity

This problem is a generalization of the classical problem of the stability of a spinning rigid body. We obtain the stability chart by using: (i) the computer algebra system MACSYMA in conjunction with a perturbation method, and (ii) numerical integration based on Floquet theory. We show that the form of the stability chart is different for each of the three cases in which the spin axis is the minimum, maximum, or middle principal moment of inertia axis. In particular, a rotation with arbitrarily small angular velocity about the maximum moment of inertia axis can be made unstable by appropriately choosing the model parameters. In contrast, a rotation about the minimum moment of inertia axis is always stable for a sufficiently small angular velocity. The MACSYMA program, which we used to obtain the transition curves, is included in the Appendix.

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.

Automatic Identification of Roadway Horizontal Alignment Information Using Geographic Information System Data: CurvS Tool

2021 ◽  
pp. 036119812110363
Author(s):  
Bekir Bartin ◽  
Sami Demiroluk ◽  
Kaan Ozbay ◽  
Mojibulrahman Jami
Keyword(s):  
Information System ◽  
New Jersey ◽  
Geographic Information System ◽  
Geographic Information ◽  
Automatic Identification ◽  
Web Based ◽  
Horizontal Alignment ◽  
System Data ◽  
Overlap Ratio ◽  
Geographic Information System Data

This paper introduces CurvS, a web-based tool for researchers and analysts that automatically extracts, visualizes, and analyzes roadway horizontal alignment information using readily available geographic information system roadway centerline data. The functionalities of CurvS are presented along with a brief background on its methodology. The validation of its estimation results are presented using actual horizontal alignment data from two different roadway types: Route 83, a two-lane two-way rural roadway in New Jersey and I-80, a freeway segment in Nevada. Different metrics are used for validation. These are identification rates of curved and tangent sections, overlap ratio of curved and tangent sections between estimated and actual horizontal alignment data, and percent fit of curve radii. The validation results show that CurvS is able to identify all the curves on these two roadways, and the estimated section lengths are significantly close to the actual alignment data, especially for the I-80 freeway segment, where 90% of curved length and 94% of tangent section length are correctly matched. Even when curves have small central angles, such as the ones in Route 83, CurvS’s estimations covers 71% of curved length and 96% of tangent section length.

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