The time taken and distance travelled by the train if running at 50kmph or. Steam locomotive tractive effort vs diesel electric. The term tractive effort is often qualified as starting tractive effort, continuous tractive effort and maximum tractive effort. Ac traction vs dc traction greenville, south carolina. 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. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs a g acceleration of. This is specifically in reference to wheels and road surfaces. Tractive effort determines how much a locomotive can haul. Throughout the years, official tractor performance drawbar tests have been conducted on hard surfaces.
The tractive force between a car wheel and the surface can be expressed as. Influence of locomotive tractive effort on the forces between wheel and rail article pdf available in vehicle system dynamics 35supplement. Pdf on jan 1, 2012, anton rassolkin and others published calculation of the traction effort of switching. Pdf influence of locomotive tractive effort on the. Multitrain simulation of dc rail traction power systems with.
The merge was done by selecting the highest measured value of tractive effort for the given speed. Gunter venter deutsche bahn ag research and technology centre verification and testing, traction, tzf 74 germany, volckersta. The recorded and calculated values of the coefficient of traction based on the. The amount of the offsets depends on the motion resistance force mr, the tire loaded radius.
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. Calculating tractive effort page 1 locomotives and. Evaluation of advantages of highspeed emus in the case of. Locos are rated at horsepower for traction which basically means the hp of the diesel engine after the hp for accessories such as pumps and fans has been subtracted. One percent of a ton or 2000 pounds equals 20 pounds. Starting tractive effort, found in the locomotive data sheet, is the rated tractive effort starting from a standstill in run8.
The impact of maximizing tractive effort on rail track wear damage is quantified. Tractive effort definition of tractive effort by merriam. A car accelerates 1800m down an incline of 1 in 4 at 0. Pdf calculation of the traction effort of switching.
Is the maximum tractive effort of a vehicle dependent on. The car has a mass of 4,000kg and the resistance to motion is 400n determine. In equation 1 f is the tractive effort applied by the motor, r is the resistance f force that depends on the dimensions and the velocity of the train and friction coefficients of the track section, fg and fc are gradient and curve forces that depend on the gradient and radius of the track at the position of the train see. Braking and traction forces depend on the normal force and adhesion coefficient at the wheelrail contact area. In the main line train, tractive effort is caused by the locomotive, and in a suburban train, it is caused by motor coaches. Pdf vehicle tractive force prediction with robust and windupstable. But when clipping along with one of those, you can crack the throttle and spin the wheels. Why do diesel locomotives have maximum tractive force. I need to know exactly what the difference is between traction and tractive force. So the laboratory answer is that tractive effort is independent of power, but power is composed of force tractive effort, distance and time.
Vehicle dynamics calculation tractive effort of a car. F traction effort or force acting on the wheel from the surface n, lb f. An important factor in determining the continuous tractive effort of any vehicle with an electric transmission especially dieselelectric. Just multiply the traction effort in kilo newtons kn by the velocity in meters per second and you will have the power in kilo watts kw. I can find definitions of traction but nothing really on tractive force. Five dimensionless parameters are used to describe tractive performance. This thesis will combine the above mentioned subsystems by taking advantage of the above. Nexsys iiii improving locomotive adhesion, performance, diagnostics, and overall efficiency with this advanced, proven and reliable control system. Traction motor in some trains provide a certain number of notches for acceleration and braking, in other words the tractive effort is discrete, whereas in other trains the tractive effort is continuous which is like the gas pedal in cars. Measuring traction power and rolling resistance of model. It is the amount of force a wheel can apply to a surface before it slips. These terms apply to different operating conditions, but are related by common mechanical factors.
The percent of grade is perhaps the most important factor governing tractive effort. 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. 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. A locomotives tractive effort at all speeds is limited by its adhesive weight and the available coefficient of adhesion between wheel and rail, as illustrated in the above diagram and as discussed in more detail on the adhesion page of this website the maximum speed that a locomotive can attain with any given train occurs when the locomotives drawbar tractive effort exactly equals. In other words, it is the sum of the tractive force and rolling effort on the road surface. Available tractive effort road vehicle performance. Our markets with over 300 new movers coming into the north american annually, there is a good market for industrial locomotives. Multitrain simulation of dc rail traction power systems. Using the motor characteristics and the line voltage determine the maximum tractive effort or maximum braking tractive effort depending on the required tractive effort possible with the current speed of the train. A wheel will have different traction on different surfaces, as, the coefficient. Jan 07, 20 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.
The total axle torque is tractive effort times the wheel radius. Moreover, the paper presents calculation of the traction effort of tep70. Tractive effort is the force needed to simply move the train. Tractive effort versus horsepower trains magazine trains. Innovative method for measuring the tractive effort of rail vehicles dr. To do this we will use the maximum tractive effort calculated in equation 9 which was 100 lbs. Calculating tractive force using two methods physics forums. The tractive power models are competitively priced and tractive power corporation can offer a longterm leasing and service plan for qualified customers. The maximum permissible traction force that can be applied to the wheels is governed by two things. Optimal control of an emu using dynamic programming and.
Jun 22, 2017 tractive effort te is the force applied by a locomotive for moving itself and a train. A rubbersurfaced and frictionbased prototype track was developed and mounted on the patented modification of a new allis chalmers four wheel drive tractor. 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. Force of vehicles engine maximum value transferable maximum tractive effort define the point at which additional enginegenerated tractive effort is not productive. Tractive effort and tractive resistance c12 springerlink. Traction effort of switching locomotive chme3 with railroad slope 0. The higher your speed, the lower your locomotives tractive effort. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs. The ztr control systems and tractive effort solutions are designed to improve the performance, reliability and availability of existing locomotive fleets at a fraction of the cost of buying new locomotives.
Influence of locomotive tractive effort on the forces between. Tractive effort of steam locomotives locomotive ratiosii. Power is the force needed to run a train at a certain speed. Even if widening on the throttle at speed you probably wont see much more than 300 amps anyway. We combine decades of rail experience and a worldleading position in areas such as. Readhesion control strategy based on the optimal slip velocity. A 1% grade is defined as a vertical increase of one foot for each 100 feet of horizontal distance. Traction effort of switching locomotive chme3 with railroad slope 5. Traction systems for locomotives and high speed applications.
The tractive effort column is the theoretical tractive effort of a 3,000 hp loco for each speed. On higher speed vehicles friction in drive components may warrant the addition of 10%15% to the total tractive effort to ensure acceptable vehicle performance. The simulink package used for modelling railway traction drives represents an interesting. So if they could handle the tractive effort of 80 000, then the engineer should not drive below 9. Travel reduction ratio trr, commonly called slip and expressed in percent. The main goal of the study is to change the tractive force of a tep70 locomotive to be able to. Above that speed, the locomotive doesnt have enough power to generate that much force, and is now following the formula fpv. Net traction ratio ntr, sometimes called pullweight ratio. Traction can be defined as the friction between a drive wheel and the surface it moves upon. 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. Tractive effort te is the force applied by a locomotive for moving itself and a train. The available traction effort goes down as the speed or velocity goes up.
When im playing openttd sometimes i come across a powerful locomotive from 4000 hp and up that have lower te then some less powerfull locos 3600 hp and down so im wondering, is the trade off for tractive effort worth the extra power or would i just be better doubling up less powerful but high traction locos, even when the power of another loco might be more then 2 less powerful locos. In detail the resistant force fw can be devided in an acceleration force fwa, an inclination force fwn, a curve force fwb and a running force fwl. When moving up in the slope the drive has to produce tractive effort to overcome the force due to gravity. Particularly, recent power electronics technology has realized a lightweight and compact traction system. The speed at which both forces are equal is the maximum speed. Examine a free body diagram maximum tractive effort l wheelbase h height of the center of gravity l f, l r. The primary advantages of ac traction are adhesion levels up to 100% greater than dc and much higher reliability and reduced maintenance requirements of ac traction motors. For every ton of train weight in a grade, 20 pounds of tractive effort is needed for each 1% of slope. With this in mind, there are two places we can get tractive effort. Control systems and tractive effort ztr control systems, llc. Innovative method for measuring the tractive effort of.
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. As with power, there are different methods of measuring tractive effort. Whatever may be source or principle of working of traction motor, all provide tractive effort characteristics to encounter train resistance and provide acceleration. Is the maximum tractive effort of a vehicle dependent on rolling resistance or the road adhesion.
As with power there are different methods of measuring tractive effort. The traction threshold speed, where tractive effort is exactly high enough to make full use of engine power, can be calculated by solving for vpft, where ft is tractive effort, p power, and v velocity in ms kph3. Tractive effort of steam locomotives locomotive ratiosii by a. The total tractive effort tte is the sum of the forces calculated in steps 1, 2, and 3. Figure shows how velocity ratio and pull ratio combine for overall. 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. Steam engines have relatively lower starting tractive effort, around 25% of the weight on the drivers, rule of thumb. Horsepower and tractive effort the idiots guide to. I suggest merging this article in to traction engineering, as that title covers this and other topics please see talk. Pdf calculation of the traction effort of switching locomotive. Tractive effort is defined as the force at the rims or the outer edges of the driving wheels of moving trains.
For slopes, you will need an additional 100 newton per percent of steepness. Emus, the traction system equipment can be distributed over a trainset, and tractive axles throughout the trainset can obtain the required tractive effort without executing a heavy axle load. Tractive motor is a class of electric motor which has the characteristics to match the load requirement of traction such as high starting tractive effort and selfcorrective action with variable. Calculation of the traction effort of switching locomotive. W weight or vertical force between wheel and surface n, lb f m mass on. The tractive effort required to overcome the force due to gravity. May 12, 20 the most important source to provide traction mechanics train, grade, curve and acceleration resistance power in the locomotive is traction motor. Railway traction vehicle electromechanical simulation. Ac traction for locomotives is a major improvement over the old dc systems. Braking effort shall not exceed 750kn distributed over all axles for a train of 5000t when adhesion is at 0. Theres another usage for these terms in the railroad business.
However, with the manual control, it was rather difficult to keep the. Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228. That kind of calculations are very important for motion planning and it should be done in order to avoid overloading. When it comes to controlling a train, driver has the direct control on the tractive effort of the train. Nov 18, 2006 difference between traction and tractive force. The tractive effort of a locomotive whether ac or dc is defined by the equations. Tractive efficiency te, usually thought of as percent but used as a ratio in this paper. Resistance bound to the slope of 2% will oppose a force of fp 220 tons x 9,806 knewton x 2 100 64,7 kn.
Tire mechanics equates it to coulombs friction force which is dependent on road adhesion. Available tractive effort tractive effort determined by. Tractive effort is a short article largely covered here and anything that is not should be merged. Sep 22, 2006 tractive effort determines how much a locomotive can haul. So if we look at an ac6000 compared to an ac4400, assuming the weight, traction motors and gear ratio are all the same, they are likely to haul the same load over a given. Influence of locomotive tractive effort on the forces. Total tractive effect required for accelerating the train on a level track. With the three cylinder locos the nsw d5758 class had that, the tractive effort was, d57 class.
Traction characteristics from each test were merged into one characteristic. The speed at which both forces are equal is the maximum speed the train can get to on a flat piece of track. Tractive effort te and tractive resistance tr tractive effort te. Find the corresponding required tractive effort using equation 1. The necessary tractive effort f t 220000 mass in kg x 0,23148 acceleration 50926 newtons, or. Delivering significant tractive effort improvements, adhesion control and reliability through advanced wheel slip control.