Railway Transition Curves Curvature—Should It Be Smooth in the Extreme Points or Not, or Something Else?
Year: 2025
Type: article
Abstract: This work addresses the features of railway transition curves’ curvature, especially at extreme points. In particular, should it be smooth at the extreme points or not, or something else? Such a question is not accidental. This is based on the main results that the present authors obtained while optimizing the shape of polynomial railway transition curves. It appeared for the same quality function, that depending on the transition curve degree, the optimum shapes represented curvatures either possessing bends or close to smooth at the extreme points. Such a discrepancy raises the question of its reason, i.e., the factor influencing most the appearance of bends at the extreme points of the curvatures. The continuity of G0 and G1 at such points was considered. At the same time, the hypothesis was formulated that a long time while negotiating the curve is the factor mostly influencing the existence of the mentioned bends in the extremities of curvature. Two cases were considered to ensure the long time of vehicle passage through the curve, with a great curve length and a small vehicle velocity, respectively. To verify the hypothesis, the optimizations of the shape of the transition curves of 5th, 9th, and 11th degrees and the simulations of the railway vehicle behaviour were performed. The hypothesis turned out to be true, however, easier in application at High-Speed Rail conditions. It was shown that the transition curves shapes got in assumed circumstances did not have the bends at the extreme points. The tendency to smooth the curvature can be univocally noticed. It resulted in calmer vehicle movement, expressed by vehicle body lateral dynamical characteristics. Corresponding results of the simulations and transition curve optimizations were presented and compared.
Source: Applied Sciences
DOI: 10.3390/app152212066
Authors: Krzysztof Zboinski, Piotr Woznica
Institution: Warsaw University of Technology
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
OpenAlex ID: W4416170212