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Track Brake
A magnetic track brake (Mg brake) is a brake for rail vehicles. It consists of brake magnets, pole shoes, a suspension, a power transmission and, in the case of mainline railroads, a track rod. When current flows through the magnet coil, the magnet is attracted to the rail, which presses the pole shoes against the rail, thereby decelerating the vehicle. While brakes such as disc brakes or shoe brakes depend on the frictional connection between wheel and rail, the magnetic track brake acts directly on the rail. Therefore, its brake effect is not limited by wheel-rail contact. Thus, environmental factors such as wetness or contamination of the rail have less influence on the brake force. Usage Magnetic track brakes are used on rail vehicles in addition to the primary, wheel-effective brake systems. As an additional brake system, they help to ensure that the prescribed brake distances of rail vehicles can be complied with. Since magnetic track brakes always act unregulated an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Septa PCC Car Truck
SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates transit bus, bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people throughout five counties in and around Philadelphia, Pennsylvania. It also manages projects that maintain, replace, and expand its infrastructure, facilities, and vehicles. SEPTA is the major transit provider for Philadelphia and four surrounding counties within the Philadelphia metropolitan area, including Delaware County, Pennsylvania, Delaware, Montgomery County, Pennsylvania, Montgomery, Bucks County, Pennsylvania, Bucks, and Chester County, Pennsylvania, Chester counties. It is a state-created authority, with the majority of its board appointed by the five counties it serves. Several SEPTA commuter rail and bus services serve New Castle County, Delaware and Mercer County, New Jersey, although service to Philadelphia from South Jers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knorr-Bremse
Knorr-Bremse AG is a German manufacturer of braking systems for rail and commercial vehicles that has operated since 1905. Other products in the company's portfolio include intelligent door systems, control components, air conditioning systems for rail vehicles, torsional vibration dampers, and transmission control systems for commercial vehicles. The Group has a presence in over 30 countries, at 100 locations. In 2022, the Group's workforce of over 31,000 achieved worldwide sales of EUR 7.15 billion. History Foundation and early years The Germany engineer Georg Knorr established ''Knorr-Bremse GmbH'' in 1905 in Boxhagen-Rummelsburg, Neue Bahnhofstraße, outside Berlin (since 1920 part of Berlin-Friedrichshain). From the onset, the company benefitted heavily from Knorr's prior experience working on railway braking systems at, ''Carpenter & Schulze'', a separate company that he owned. Knorr promptly put into production an innovative rapid release brake that could b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength and low raw material cost, steel is one of the most commonly manufactured materials in the world. Steel is used in structures (as concrete Rebar, reinforcing rods), in Bridge, bridges, infrastructure, Tool, tools, Ship, ships, Train, trains, Car, cars, Bicycle, bicycles, Machine, machines, Home appliance, electrical appliances, furniture, and Weapon, weapons. Iron is always the main element in steel, but other elements are used to produce various grades of steel demonstrating altered material, mechanical, and microstructural properties. Stainless steels, for example, typically contain 18% chromium and exhibit improved corrosion and Redox, oxidation resistance versus its carbon steel counterpart. Under atmospheric pressures, steels generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wear
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology. Wear in machine elements, together with other processes such as fatigue and creep, causes functional surfaces to degrade, eventually leading to material failure or loss of functionality. Thus, wear has large economic relevance as first outlined in the Jost Report. Abrasive wear alone has been estimated to cost 1–4% of the gross national product of industrialized nations. Wear of metals occurs by plastic displacement of surface and near-surface material and by detachment of particles that form wear debris. The particle size may vary from millimeters to nanometers. This process may occur by contact with other metals, nonmetallic solids, flowing liquids, solid particles or liquid droplets entrained in flowing gasses. The wear rate is affected ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pneumatics
Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems. Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically-powered compressor powers cylinders, air motors, pneumatic actuators, and other pneumatic devices. A pneumatic system controlled through manual or automatic solenoid valves is selected when it provides a lower cost, more flexible, or safer alternative to electric motors, and hydraulic actuators. Pneumatics also has applications in dentistry, construction, mining, and other areas. History Although the early history of pneumatics is somewhat unclear, blowguns are often considered the earliest pneumatic device, being created independently by various indigenous groups around the world. Bellows are an early form of air compressor used primarily for smelting and forging. Ctesibius of Alexandria is often considered the father of pneum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (device)
A spring is a device consisting of an Elasticity (physics), elastic but largely rigid material (typically metal) bent or molded into a form (especially a coil) that can return into shape after being compressed or extended. Springs can Energy storage, store energy when compressed. In everyday use, the term most often refers to coil springs, but there are many different spring designs. Modern springs are typically manufactured from spring steel. An example of a non-metallic spring is the Bow (weapon), bow, made traditionally of flexible Taxus baccata, yew wood, which when Bow draw, drawn stores energy to propel an arrow. When a conventional spring, without stiffness variability features, is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length (this approximation breaks down for larger deflections). The ''rate'' or ''spring constant'' of a spring is the change in the force it exerts, divided by the cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallel (geometry)
In geometry, parallel lines are coplanar infinite straight line (geometry), lines that do not intersecting lines, intersect at any point. Parallel planes are plane (geometry), planes in the same three-dimensional space that never meet. ''Parallel curves'' are curves that do not tangent, touch each other or intersect and keep a fixed minimum distance. In three-dimensional Euclidean space, a line and a plane that do not share a point are also said to be parallel. However, two noncoplanar lines are called ''skew lines''. Line segments and Euclidean vectors are parallel if they have the same direction (geometry), direction or opposite direction (geometry), opposite direction (not necessarily the same length). Parallel lines are the subject of Euclid's parallel postulate. Parallelism is primarily a property of affine geometry, affine geometries and Euclidean geometry is a special instance of this type of geometry. In some other geometries, such as hyperbolic geometry, lines can have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Battery
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive Terminal (electronics), terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach the positive terminal, thus causing a redox reaction by attracting positively charged ions, or cations. Thus, higher energy reactants are converted to lower energy products, and the Gibbs free energy, free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary battery, Primary (single-use or "disposable") batter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissipation
In thermodynamics, dissipation is the result of an irreversible process that affects a thermodynamic system. In a dissipative process, energy ( internal, bulk flow kinetic, or system potential) transforms from an initial form to a final form, where the capacity of the final form to do thermodynamic work is less than that of the initial form. For example, transfer of energy as heat is dissipative because it is a transfer of energy other than by thermodynamic work or by transfer of matter, and spreads previously concentrated energy. Following the second law of thermodynamics, in conduction and radiation from one body to another, the entropy varies with temperature (reduces the capacity of the combination of the two bodies to do work), but never decreases in an isolated system. In mechanical engineering, dissipation is the irreversible conversion of mechanical energy into thermal energy with an associated increase in entropy. Processes with defined local temperature produce ent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat
In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, atomic, or molecular particles, or small surface irregularities, as distinct from the macroscopic modes of energy transfer, which are thermodynamic work and transfer of matter. For a closed system (transfer of matter excluded), the heat involved in a process is the difference in internal energy between the final and initial states of a system, after subtracting the work done in the process. For a closed system, this is the formulation of the first law of thermodynamics. Calorimetry is measurement of quantity of energy transferred as heat by its effect on the states of interacting bodies, for example, by the amount of ice melted or by change in temperature of a body. In the International System of Units (SI), the unit of measurement for he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Robert and Halliday, David (1960) ''Physics'', Section 7-5, Wiley International Edition The kinetic energy of an object is equal to the work, or force ( F) in the direction of motion times its displacement ( s), needed to accelerate the object from rest to its given speed. The same amount of work is done by the object when decelerating from its current speed to a state of rest. The SI unit of energy is the joule, while the English unit of energy is the foot-pound. In relativistic mechanics, \fracmv^2 is a good approximation of kinetic energy only when ''v'' is much less than the speed of light. History and etymology The adjective ''kinetic'' has its roots in the Greek word κίνησις ''kinesis'', meaning "motion". The dichoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, electric currents, and electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function (mathematics), function assigning a Euclidean vector, vector to each point of space, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
