Simulation And Analysis Of Energy Savings From Top Of Rail Friction Modefier On Heavy-Haul Railways

While rail transportation has a considerable advantage in energy-saving and emission reduction compared with other transportations, rail transit systems in our country consumes enormous energy still. As a consequence, the research on measures of railway vehicle energy-saving and emission reduction has great realistic economic significance, also conforms to the national strategic needs. The fundamental difference between rail system and other ways of transportation is that a train runs on the track. Therefore, due to the wheel/rail relationship plays an indispensable role in rail transit systems, it is an important research orientation from the wheel/rail relationship point of view to explore measures in energy-saving and emission reduction of the train.In this study, an energy-saving prediction model is established combined with vehicle system dynamics, friction work theory and running resistance energy consumption theory based on the impact of rail of top friction modifier to the curve of wheel/rail creepage/force relationship. Through the field testing of the rail tread profiles on Shuohuang Railway, the dynamic performance and prediction energy-saving of the vehicle were analyzed by the method of numerical simulation under different typical line conditions with the Top of Rail (TOR) friction modifier (FM) applied. The study on controlling the potential of energy saving through the application with TOR FM is of great importance from the wheel/rail relationship point of view on heavy haul systems, an introduction and the main findings of this study includes:1. An energy-saving prediction model is established combined with vehicle system dynamics, friction work dissipated at the wheel/rail contact area and running resistance energy consumption theory. Literature review on friction modifiers and modelling of friction modifiers are given, considered that it can not only lowering the saturated COF at the wheel/rail interface, but also affect the curve of wheel/rail creepage/force relationship. And the effect of frction modifier on the calculation of wheel/rail forces is simulated. At last, a numerical program is coded according to relative model.2. A field research of the rail on Shuohuang Railway(SHR) is conducted and rail tread profiles of typical radius curves are measured. At the same time, the characteristics and laws of rail abrasion on different radius curves are found out and provided the basis calculation of friction power and energy-saving.3. The influence due to the application of TOR FM on vehicle dynamic performance is analyzed with the developed vehicle dynamics model. Simulation results show that the existence of friction modifier on the wheel/rail interface can obviously improve the vehicle’s lateral stability and reduce the the lateral vibration of the carbody and also have less effect on the indexes such as wheel/rail vertical force, rate of wheel load reduction and vertical stability of the carbody, but there is still improvement to a certain extent. The whee/rail forces and derail coefficient will arise with the application of TOR FM in some special operating conditions, but will not affect operation safety. So overall, the vehicle operating process is safe and stable due to the application of a friction modifier.4. The energy-saving achieved by applying TOR FM is calculated and analyzed under different operation conditions such as track curve radius, new and worn rail profile, rail cant, as well as running speed and the economy caused by energy saving is studied at the same time. Simulation results show that rail’s worn profiles have a more significant influence on energy-saving in small radius curves than large radius curves and tangent line. The effect of energy saving becomes more significant with increasing train speed when TOR FM is applied. The energy saving was observed to be more significant on a larger rail cant and this effect is more sensitive on worn rails. Preliminary economic analyses show that the application of TOR FM on curves which the radius is less than 1500 m helps SHR save 11.2 million kWh electricity every year.