This means that the locomotive must have at least 74. First we need enough power on the wheels and second enough weight to prevent the wheels from spinning. While cylinder tractive force and rail tractive force should ideally be the same, in reality there is frictional resistance in crossheads, crank pins, axle. So if they could handle the tractive effort of 80 000, then the engineer should not drive below 9. Locomotive tractive effort and power calculations tractive effort calculations. Acceleration is a measure of how quickly you are gaining or losing speed. This requires an increase in horsepower for a given load while tractive effort thus. Starting tractive effort, found in the locomotive data sheet, is the rated tractive effort starting from a standstill in run8.
However, their correct designation was articulatedconsolidation or ac for short. There are various tractive effort curves available for different locomotives for different speeds, which enable the computation of. All models feature royalglide suspension system, patented cushion coupler system, simplified power train and simplified hydraulic system. Tractive effort is a measure of how well the power figure is applied to the track, acceleration i spose. Maximum tractive effort is defined as the highest tractive force that can be generated under any condition that is not injurious to the vehicle or machine. You probably know that power is tractive effort times speed, right. General aspects of railway traction what really causes the train to accelerate or br ake are the adhesion forces that appear in the wheelrail contact.
Gps tracking on smartphone for your pet directly from the manufacturer no. In the powercentralized system, however, to obtain the tractive effort, the axle load of locomotive must be heavier to avoid slip or skid. Determines tractive effort based on train performance considers rolling, acceleration and drag resistance analyze train trip times calculate train movement patterns identify power supply inadequacies pinch points. May 12, 20 tractive effort, when multiplied with speed at which the train is required to run, gives the horsepower. This list noted the factors most commonly used in england, france, germany, etc. Measurement of tractive force and the new maximum tractive. In this paper, two models for estimating single train energy consumption are presented. In order to generate this tractive effort we need two things. Crab steering inset photo allows operators to maneuver next to aircraft. Tractive effort te is the force applied by a locomotive for moving itself and a train. Specifically, horsepower is te in pounds times speed in mileshour divided by 375. The tractive effort of a steam locomotive can be calculated by. Pdf a common feature of all engines with internal combustion is the need for a gearbox. The tractive effort requires to move a vehicle in particular direction with a given torque which must be greater than the sum of the rolling resistance.
The acceleration and deceleration rate of a train depends on the tractive force. Tractive effort characteristics of a train have three regions as shown in fig. Starting tractive effort required to start and to haul ferrmed trains in slopes of 12 are. Tractive force steam locomotives calculator fx solver. Tractive effort is the force needed to simply move the train. The maximum permissible traction force that can be applied to the wheels is governed by two things. 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 produce the maximum tractive effort at each speed is available, then multiplying this percentage by. Vehicle dynamics calculation tractive effort of a car. Horsepower x 308 speed mph where 308 is 82% of 375 lbmiles per hour per hp. Tractive effort hp curves for steam locomotives a couple of weeks ago, i printed a list of the factors for boiler pressure based on data i found in an old book on articulated locomotives. Before sharing sensitive information, make sure youre on a federal government site.
Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228. 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. It also says that for really heavy freight one can doublehead the train to provide more tractive effort. The other avenue open for improvement was an in crease in train speed. Looking at al krugs c44, its 4400hp rating means around 4100 hp at the wheel rim in its most powerful speed range. Vehicle forces for driving up slope equations and calculator. In order to start a train and accelerate it to a given speed, the locomotives must develop sufficient tractive force to overcome the train s drag resistance to motion, which is a. Maximum rear wheel tractive force from drive torque, frwmax n. Instead, the engineer driving the front locomotive can also control the other locomotives via radiocontrolled computer commands. Importance of tractive effort lies with its capability to start a train on the gradient and run it up to a speed of around 30 kmph whereas that of horse power is its ability to achieve and run at the maximum permissible speed. Application of cfd to rail car and locomotive aerodynamics. Tractive effort hp curves for steam locomotives the first of these is the most obvious in its approach.
Ideal for ramp work in wet or cold weather conditions. Tractive effort curve mathematics in education and industry. The continuous tractive effort would be determined by how much electricity traction motors could handle before burning up. Influence of locomotive tractive effort on the forces between wheel and rail article pdf available in vehicle system dynamics 35supplement. In other words, it is the sum of the tractive force and rolling effort on the road surface. Our slogan is it is simple and it works tractive power corporation is a developer and manufacturer of industrial switching rail products and technology. It is the tractive force at the locomotive driving wheels drivers at the. In most cases, maximum tractive effort is developed at low speed and may be the same as the starting tractive effort. Adhesive weight is defined as the force that can be exerted by a wheel without slipping or sliding.
The blueandgold locomotives are alaska railroad icons. 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. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs a g acceleration of. In the main line train, tractive effort is caused by the locomotive, and in a suburban train, it is caused by motor coaches. The maximum traction effort co uld be calculated by 9 and 10 with respect to changing of the frictions forces with different atmosphere conditions dr y and wet surfaces. Models for estimating energy consumption of electric trai. For slopes, you will need an additional 100 newton per percent of steepness. Evaluation of advantages of highspeed emus in the case of. A database organizes locomotives into groups called depots. For a railway to operate efficiently and safely, its locomotives should be powerful enough to accelerate their trains rapidly to the maximum allowed line speed, and the braking systems must be able to bring a train reliably to a standstill at a station or signal, even on an adverse gradient. Tractive force and train resistance characteristics. The higher your speed, the lower your locomotives tractive effort. First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track.
Particularly, recent power electronics technology has realized a lightweight and compact traction system. Wheel slip may lead to stalling, damage to rail and wheel. Superconducting power cable application in dc electric. Train performance calculations considers track profile such as grade, curvature, speed limits, etc.
Unit m 6transmission in diesel locomotive objective the objective of this unit is to make you understand about the need for transmission in a diesel engine the duties of an ideal transmission the requirements of traction the relation between hp and tractive effort the factors related to transmission efficiency. Basically, tractive effort is like the locomotives grip and will play an important role on steep sloped tracks. Review of past work the earliest study of train aerodynamics reported in the literature involved smallscale wind tunnel tests performed during 1898 at purdue university 20. A more accurate method of finding the maximum speed uses an additional equation that applies to the curved part of the tractive effort graph. Characterization of locomotive tractive effort from. Tractive effort is defined as the force at the rims or the outer edges of the driving wheels of moving trains. Train resistance and tractive effort are both measurements of force typically in. Speed was sacrificed for power, and flexibility was its hallmark.
Opentrack stores each locomotives technical characteristics, including tractive effort speed diagrams, load, length, adhesion factor, and power systems. First, a force of 2 to 5 pounds per ton of train weight is. Hi there again, i am trying to correctly calculate the tractive effort pf a train, currently i do this. Tractive effort, when multiplied with speed at which the train is required to run, gives the horsepower. Tractive effort is measured in this manner on road tests since it is virtually impossible to measure tractive effort at the rail. As the train speed increases, the tractive effort from the locomotives decreases and the drawbar pull available to move the train also decreases. Southern pacific was the only major railroad in this country to use steam.
The materials used in this file have come from a variety of sources and have been assembled. I work for eversholt rail a train leasing company that owns about a. For example, a 3000 hp locomotive will have approximately 74,000 lbs. The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. F traction effort or force acting on the wheel from the surface n, lb f. A heavy freight engine would want high power and high tractive effort. Optimal control of an emu using dynamic programming and tractive effort as the control variable nima ghaviha1 markus bohlin2 fredrik wallin1 erik dahlquist1 1school of business, society and engineering, malardalen university, sweden, nima.
Until the first half of the 20th century, rail freight transport was one of the main pillars of the. 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. For steam locomotives, tractive effort was usually the limitting factor in the size of the train it could pull. Cylinders weight pressure tractive build build road no. In both the situations, it is the adhesive weight playing the most important role. The tractive force between a car wheel and the surface can be expressed as. Maneuverable coordinated steering enables tight turns, easy maneuvering on busy airport ramps. Tractive powers tp56 industrial locomotive overview. The speed at which both forces are equal is the maximum speed the train can get to on a flat piece of track. A rough assessment of the tractive effort of different types of locomotives is provided in the following sections. In railway engineering, the term tractive effort is often used synonymously. Jan 07, 20 tractive force calculation for a vehicle 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.
Pound force applied to the rear coupler to pull a train. The backbone of train simulation physics is the simple equation, fma force mass x acceleration. Both require detailed train running states outputted from train performance simulator tps or speed profile generator, including train velocity, running time, corresponding tractive effort and braking force. If the tractive effort is much greater than what is required to haul the train, the wheels of the locomotive may slip. Power is the force needed to run a train at a certain speed.
Low tractive effort will mean that even something with a high power figure will struggle to get up to speed. The tractive effort of a locomotive should be enough for it to haul a train at the maximum permissible speed. Horsepower and tractive effort the idiots guide to. The power of traction ge nerator that is needed to. So that sets some sort of ceiling to the tractive effort of any diesel.
Tractive effort and train resistance horsepower friction scribd. Analysis, evaluation and simulation of railway diesel. Pdf calculation of the traction effort of switching locomotive. Wheel slipping occurs when tractive effort exceeds adhesive weight whereas sliding occurs when braking effort exceeds adhesive weight.
Pdf calculation of the traction effort of switching. Defining tractive effort the term tractive effort is often qualified as starting tractive effort, continuous tractive effort and maximum tractive effort. Tractive effort versus horsepower trains magazine trains. This is done because the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity. A number that relates to a tractive effort on a dc motor locomotive that the traction motor can obtain indefinitely without overheating. Tractive effort is the propelling force which a locomotive exerts at the rims of its driving wheels. Optimal control of an emu using dynamic programming and. A simulated train uses one or more locomotives from a depot together with a number of passenger or freight cars carriages or wagons. Dec 27, 2017 whilst tractive effort determines the ability of the locomotive to haul heavy loads, e. The 4882 some people called the 4882s backup locomotives. What links here related changes upload file special pages permanent. Superconducting power cable application in dc electric railway systems h.
If the rear wheels of the vehicle in the figure are driven with no slip taking place between the tires and the level road surface, the wheel force or the tractive effort te is equal to the torque at the driven wheels t w divided by the rolling radius or effective radius r w. When the wheels of a train slip on the rails, the torque is decreased to avoid continuous slipping. Dieselelectric traction has the following advantages. The tractive effort of a locomotive is the force that the locomotive can generate for hauling the load.
Tractive effort, and how important it is transport. At higher speeds a tractive force decreases a little and a braking force increases when the train resistance is taken into account. As with power there are different methods of measuring tractive effort. Pdf influence of locomotive tractive effort on the forces. The maximum speed can roughly be calculated by reading the point at which tractive effort resistance to motion on the graph. Vehicle dynamics cee 320 steve muench outline resistance aerodynamic rolling grade tractive effort acceleration braking force stopping sight distance ssd main concepts resistance tractive effort vehicle acceleration braking stopping distance resistance resistance is defined as the force impeding vehicle motion what is this force. Therefore, tractive effort was more important than horsepower for steam locomotives.
Cte is non applicable for an ac traction motor, which use te only. The longer the train, the slower it will go up the hill and if you exceed the trains weight against the tractive effort, the train will slip. Total tractive effort required by both front wheels, ftf n total tractive effort of the machine, ftm n force from gravity acting along the incline, fg n. Ftk propulsive force, tractive effort of locomotiveemu k of u units in. The tractive effort in pounds available from a locomotive can be roughly calculated as. Tractive effort and train resistance free download as pdf file. As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion. For these adhesion forces to appear, tractive or braking effort needs to be applied to the wheels. With this in mind, there are two places we can get tractive effort. The classa climax used a twocylinder marine steam engine, usually located in the cab, out of sight. But it doesnt provide realistic values, so i am wondering, what is the correct way of calculating tractive effort of a train. Tractive effort is a measure of the force that a locomotive can apply to the train it is pulling. Tractive effort and dynamic braking curves were provided by go transit and are shown in figure 2.
Continuous tractive effort is the tractive force that can be maintained indefinitely, as distinct from the higher tractive effort that can be maintained for a limited period of time before the power transmission system overheats. Tireground adhesion and maximum tractive effort the slip, s, of a tire is usually defined as where v is the translatory speed of the tire center. When the locomotive is in perfect condition and is tested under constant conditions of workcutoff, speed, loadthe test will show higher figures than when the regular road locomotive is tested with a commercial train on an undulated profile and at variable conditions of work. It is usually expressed in pounds the relation between tractive effort, rail horsepower, and speed in miles per hour is tractive effort 270 rail horsepower kg speed note.
Starting tractive effort required to haul ferrmed trains. Calculating tractive effort for steam locomotives transport. But it gives no indication of the relationship between the tractive effort and the amount of cargo it can haul effectively. Material provided by sachin buddhisagar, copyright 2011. Tractive effort of steam locomotives locomotive ratiosii. Tractive effort te and tractive resistance tr tractive effort te. 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. An ordinary steam locomotive relies upon rotational force or torque developed at the driving wheels produced by the.
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