Performance of Petroleum Car Engines Around The Railway

The car accident while passing on the railroad tracks is not new anymore. Several assumptions emerged about the cause of the breakdown of the car. Some say it's because of the magnetic field that arises from the friction between railroad iron and railroad wheels. Various internet sites have discussed the problem of car accidents that often occur at train crossings, but do not include the cause of the accident. Logically, it is true that the friction between two metals will cause something that according to physics is called thermal energy in the form of heat. The heat generated by the friction of the railroad tracks and wheels is certainly not the cause of these accidents. In several previous studies, it was stated that the friction between the wheels and railroad tracks causes changes in the earth's magnetic field. The change in the earth's magnetic field is not yet known whether it affects the performance of a car engine. This research will look for the effect of changes in the earth's magnetic field on the performance of car engines. The engine performance under study is to compare car engine speed between car engine speed data due to changes in the earth's magnetic field with car engine speed data without the influence of changes in the earth's field using the t test method for two paired samples. The results of the data test show that changes in the earth's magnetic field do not affect the performance of a car engine speed.

Effect of Alloy Elements in Time Temperature Transformation Diagrams of Railway Wheels

The Heavy-Haul railroad wheels started to use higher wear resistance steels microalloyed with niobium, vanadium, and molybdenum [1]. During continuous cooling, these elements depress the temperature of the pearlite formation, producing smaller interlamellar spacing that increases the hardness of the steel, besides to favor the precipitation hardening through the formation of carbides [2, 3]. Also, they delay the formation of difusional components like pearlite and bainite during isothermal transformation. The effects of these alloy elements on microstructure during isothermal transformation were studied in this work using a Bähr 805A/D dilatometer. Three different compositions of class C railway wheels steels (two microalloyed and one, non microalloyed) were analyzed in temperatures between 200 and 700 °C. The microstructure and hardness for each isothermal treatment were obtained after the experiments. Comparing with non microalloyed steel (7C), the vanadium addition (7V steel) did not affect the beginning of diffusion-controlled reactions (pearlite and bainite), but delayed the end of these reactions, and showed separated bays for pearlite and bainite. The Nb + Mo addition delayed the beginning and the ending of pearlite and bainite formation and also showed distinct bays for them. The delays in diffusion-controlled reactions were more intense in the 7NbMo steel than in 7V steel. The V or Nb + Mo additions decreased the start temperature for martensite formation and increased the start temperature for austenite formation.

Increasing the wear resistance of steel bandage by surface laser modification with tungsten carbide particles

Currently, the wheel flange limiting wear is the main reason of the railroad wheels trueing. In order to enhance the wear resistance of the wheels to the required level, composition of their surface shall be changed, which is proposed to do by the method of laser surface modification introducing spherical particles of tungsten monocarbide with diameter from 50 to 150 μm. It was found out that introduction of the said particles into steel, which composition corresponds to grade 2 as per GOST 398-2010, results in reduction of microhardness of matrix metal formed on the composite layer surface as long as the content of tungsten monocarbide particles is increased. This phenomenon shall be probably connected with the change of chemical composition and stress-strain state of metal. Examination of wear resistance using roller samples demonstrated that growth of the volumetric fraction of reinforcing particles significantly increases the wear resistance. Laser heat processing of the surface without introducing the particles results in the wear resistance increase too. Wear and tear of the counter rollers cut from the rail operated in pair with the reinforced rollers cut from the tread band is less than in the pair with untreated rollers. Introduction of reinforcing particles is much more important than matrix hardening for increasing the wear resistance. It is demonstrated that cross-crack defects can be formed in modified layers, which quantity depends on the volumetric fraction of reinforcing particles. When content of tungsten monocarbide is less than 10%, cracks are not observed. According to the totality of properties, the best content of reinforcing particles shall amount from 8 to 10% of the volume.

Effect of temperature on the performance of railroad wheels

Sliding and tread brake heating are known to alter microstructures and properties and show causal relationships with shelling and spalling. Temperature can also affect the performance of wheels in other ways: rolling contact forces depend on the size of the contact patch, which is affected by the elastic modulus, which in turn is affected by the tread temperature. Temperature differences from the rim to the remaining portion of the wheel may cause distortions, which may result in unfavorable contact between the wheel and the rail. Cold temperatures affect the fracture toughness and, in the presence of water, may cause wedging, which will accelerate the shelling process. Oxidation within a crack can also cause wedging, resulting in the propagation of thermal cracks. Changes in the residual stress due to brake heating can also affect shakedown. This study considers the many ways of how temperature can affect the performance of the railroad wheel of a freight car. Most of the author’s observations relate to the freight car service in North America and may not be applicable to other types of service in other parts of the world.