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Noise and Vibration from Railway Vehicles
Published in Simon Iwnicki, Maksym Spiryagin, Colin Cole, Tim McSweeney, Handbook of Railway Vehicle Dynamics, 2019
David Thompson, Giacomo Squicciarini, Evangelos Ntotsios, Luis Baeza
To reduce impact noise, it is clearly desirable to remove the cause if this is possible. Wheel flats can be largely prevented by installation of wheel-slide protection equipment. Monitoring equipment is now widely used to identify wheels with flats, to allow them to be removed from service as quickly as possible for reprofiling. On main lines, jointed track has been mostly replaced by continuously welded rail in the last 40 years, although inevitably, joints remain such as expansion joints, track-circuit insulating joints and switches and crossings. Even so, measures such as swing-nose crossings allow the impact forces, and thus noise, to be minimised. Attention should also be given to ensuring that welded rail joints are as levelled as possible by using rail-straightening equipment.
Improved modelling of trains braking under low adhesion conditions
Published in Tribology - Materials, Surfaces & Interfaces, 2020
Hamid Alturbeh, Roger Lewis, Klaus Six, Gerald Trummer, Julian Stow
The LABRADOR model has been developed in MATLAB/Simulink software. The model has been developed to represent the complex behaviour of modern multiple unit passenger trains braking in normal and low adhesion conditions. It is modular to allow easy specification of vehicle, bogie and wheelset subsystems. Figure 1 shows a block diagram of the LABRADOR model in which the train module interacts with the environment model and driver brake demand model as inputs. In LABRADOR's modular structure the train module contains one, two, three, or four functionally identical vehicle modules, each vehicle module contains a number of functionally identical wheelset modules. Within the wheelset module, wheel slide protection (WSP) (an automatic system used to detect and prevent wheel slides during braking or acceleration) and friction braking, sanding, dynamic braking, and wheel and contact patch subsystems exist. The contact patch module contains the contact patch temperature, contact patch dimension and adhesion creep curve modules. The following subsections summarize the functions of the train brake system modules.