The term tractive effort is often qualified as starting tractive effort, continuous tractive effort and maximum tractive effort. The tractive effort of a locomotive is the force that the locomotive can generate for hauling the load. A simulated train uses one or more locomotives from a depot together with a number of passenger or freight cars carriages or wagons. So if they could handle the tractive effort of 80 000, then the engineer should not drive below 9.
It is said that the tractive force between the wheel and the rail depends on the slip. The main goal of the study is to change the tractive force of a tep70 locomotive to be able to transport cargo in the baltic region. A year later it began acquiring the wide cab version and altogether wound up with more than 1,200 by the time ge ended production in 2004. Tractive effort is a result of available horsepower and weight on drivers just as a muscle car can have so much power that itll spin its tires easily, so too can a loco. The constants 3 and 20 in equation 32 indicate that an average car has a rolling resistance of. The continuous tractive effort would be determined by how much electricity traction motors could handle before burning up. Calculating tractive effort for steam locomotives when modeling a set of train vehicles, an important information needed for the dynamics of a locomotive is max tractive effort te, resp max te, which is determining the ability of a locomotive to pull up a train. What are the two primary aspects of transportation energy efficiency. The power of traction ge nerator that is needed to.
There are various tractive effort curves available for different locomotives for different speeds, which enable the computation of. Horsepower and tractive effort the idiots guide to. I work for eversholt rail a train leasing company that owns about a. Tractive effort is the ability of the locomotive to transfer power from the engine to the tracks. Tractive effort and resistance to motion tractive effort resistance to motion i have extended the speed range on the graph to show the point where the resistance to motion gets larger than the tractive effort. Tractive effort definition of tractive effort by merriam. Things like this make the game really difficult to play intuitively, because this information is not readily available and immediately clear to the player. As thork said, the power rating gives you the resulting calculation for a train based on the empty running weight. Improved tractive effort enhanced reliability intuitive diagnostic interface flexible options superior train handling and control. Pound force applied to the rear coupler to pull a train. A number that relates to a tractive effort on a dc motor locomotive that the traction motor can obtain indefinitely without overheating. Another possibility for computer simulations consists in the.
Steam engine valve gear on the computer downloadable freeware simulations of every kind of valve gear youve ever heard of by charles dockstader ca. After some of the tractive effort is used to move the locomotive itself, the remaining effort. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs a g acceleration of. If the rear wheels have such a torque applied to them that they are on the. A wheel will have different traction on different surfaces, as, the coefficient. The tractive power models are competitively priced and tractive power corporation can offer a longterm leasing and service plan for qualified customers. These terms apply to different operating conditions, but are related by common mechanical factors.
Tractive effort definition is the force in pounds exerted by powered equipment as a locomotive as measured for statistical purposes at the rim of the driving wheels. The tractive effort required to overcome the force due to gravity. We will be begin by discussing tractive effort or tractive force, which is the amount of force at the wheels available for moving a train. In both the situations, it is the adhesive weight playing the most important role. Whatever may be source or principle of working of traction motor, all provide tractive effort characteristics to encounter train resistance and provide acceleration. Pdf influence of locomotive tractive effort on the forces between. Tractive power the tractive power of a locomotive should be adequate enough to overcome these resistances and haul the train at a specified speed. This was a vast increase over the sd50, and even the sd38 and sd40 series, as those models generally offered between 80,000 to 90,000 pounds of tractive effort. As the train speed increases, the tractive effort from the locomotives decreases and the drawbar pull available to move the train also decreases. Starting vs continuous tractive effort trains magazine. The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. Usable locomotive tractive effort at desired speed lb.
Wg gross weight of representative car tons, from table 37. Wet rail will knock adhesion down to about 18%, but sand will get you back to 2225%. At very slow yard speeds only 2 to 3 pounds is needed while increasing to about 5 pounds at higher speeds. The maximum permissible traction force that can be applied to the wheels is governed by two things. If a cross over the tractive effort curve woul d appear for the next gear by. The boaii not only improves locomotive tractive effort, but it provides operation protection and reliability for better train handling, adhesion and performance. Opentrack stores each locomotives technical characteristics, including tractive effort speed diagrams, load, length, adhesion factor, and power systems. Pdf calculation of the traction effort of switching locomotive. First, tractive effort is a function of weight on drivers and the factor of adhesion. In railway engineering, the term tractive effort is often used synonymously with tractive force to describe the pulling or pushing capability of a locomotive. Emus, the traction system equipment can be distributed over a train set, and tractive axles throughout the train set can obtain the required tractive effort without executing a heavy axle load. Evaluation of advantages of highspeed emus in the case of.
Adhesive weight is defined as the force that can be exerted by a wheel without slipping or sliding. In order to determine the train mass that a loco motive can. Calculating tractive effort page 1 locomotives and. General by electric traction is meant locomotion in which the driving or tractive force is obtained from electric motors. G5t 2 up to 5400 up to 5400 haulage capacity for wag5tao locomotive 3 step weak field gr 15. If a cross over the tractive effort curve would appear for the next gear by remaining in gear until maximum rpm, then a small, roughly triangular shaped section would be cut out of the available area every time when gear is changed. So our first guess at a tevsspeed curve is a hyperbola.
Locomotive boilers and engines 12mb pdf file 1920 purdue university treatise on locomotive boiler and engine design, construction, and operation. Drawbar tractive effort the force applied by a locomotive to the connection to its train. Total tractive effect required for accelerating the train on a level track. Train resistance and tractive effort are both measurements of force typically in pounds in north. A database organizes locomotives into groups called depots. Tractive effort is a function of mean effective pressure of the steam cylinder and is expressed by following formula for a simple. To back this up, it also offered substantial continuous tractive effort of 98,250 pounds starting and 100,000 pounds continuous using gms new d87b traction motor. These engines are now being rapidly replaced by electric engines 43.
When moving up in the slope the drive has to produce tractive effort to overcome the force due to gravity. The tractive effort of a locomotive should be enough for it to haul a train at the maximum permissible speed. The first of these is the most obvious in its approach. Cte is non applicable for an ac traction motor, which use te only. Tractive force or tractive effort or traction is the force applied between the tire and road surface to move a car or any vehicle for that matter. By the way, the term tractive effort is supposed to imply at the wheel rim, as opposed to at the locomotive coupler. F traction effort or force acting on the wheel from the surface n, lb f. Measurement of tractive force in the creep region and maximum. Starting tractive effort, found in the locomotive data sheet, is the rated tractive effort starting from a standstill in run8. The magnitude and direction of these forces are calculated for equilibrium curving of a conventional twoaxle bogie in curves of 6001800 m radius, both without traction and for a level of tractive effort of 0. The tractive force between a car wheel and the surface can be expressed as. First we need enough power on the wheels and second enough weight to prevent the wheels from spinning. First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track.
Remember, trains cannot stop quickly, so in the simplest manual. The rolling resistance of a train on straight level track is approximately 10 lbs. We must also add the weight of the locomotive which we will say is 400 lbs. The rolling resistance of a train on straight level track is approximately. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Analysis of tep70 working principles and load characteristics. It is the amount of force a wheel can apply to a surface before it slips. Tractive effort, curving and surface damage of rails. To move any object, a force must be applied to overcome the resistance or inertia of the resting object. If the locomotive is running light with no train then its. In order to generate this tractive effort we need two things. Traction can be defined as the friction between a drive wheel and the surface it moves upon. The tractive effort estimation formula, which i found in a paper from virginia tech university. Traction and curving are the principal causes of high tangential forces between railway rails and wheels.
The speed at which both forces are equal is the maximum speed the train can get to on a flat piece of track. The adhesions factor depends on the translation speed of the vehicle and the gliding speed of wheel on rails, from empiric laws described on figures 3. Tractive effort of steam locomotives locomotive ratiosii. With the advanced antislip mechanisms now in use, i would imagine that its a lot easier to. This means that the locomotive must have at least 74. The speed at which both forces are equal is the maximum speed the train. Traction motor used for traction purpose is dc series motor, separately excited dc series motor, three phase induction motor, synchronous motor and permanent magnet synchronous motor. Based on the capacity of a boiler to produce steam, a tractive effort curve is drawn by calculating what percentage of the steam needed to. Te is the tractive effort n r w is the rolling radius or effective radius m. Tractive effort values in tonnes at various speeds up to up to 5093 5400 table no.
Resistance due to friction resistance due to friction is the resistance offered by. Our markets with over 300 new movers coming into the north american annually, there is a good market for industrial locomotives. This characteristic detail is somewhat mysterious, and is unfortunately. Wheel slipping occurs when tractive effort exceeds adhesive weight whereas sliding occurs when braking effort exceeds adhesive weight. This will effect both acceleration and the ability to hill climb. Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228. Vehicle dynamics calculation tractive effort of a car. The tractive force ft in the contact area between the tires of the driven wheels and to determine the maximum tractive effort, that the tire ground contact can. With the three cylinder locos the nsw d5758 class had that, the tractive effort was, d57 class. Factor of adhesion for a dc locomotive is usually taken as 2225% on dry jointed rail. For example the canadian set has coal wagons that limit the train s speed to 128 however, you also need a van in the back of the train or the train s speed is halved.
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