Dec 26, 2011 bachmann locos class 20, 37 and 66 vitrains class 37 pulling force one couplers all data are in metric grams. Train acceleration calculator transport fever general. 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. Tractive effort is the force needed to simply move the train. Travel reduction ratio trr, commonly called slip and expressed in percent. In the main line train, tractive effort is caused by the locomotive, and in a suburban train, it is caused by motor coaches. With this in mind, there are two places we can get tractive effort. The total axle torque is tractive effort times the wheel radius. Hello this is my last questions i have to finish the year, the problem im having is finding the correct way to work it out. In the main line train, tractive effort is caused by the locomotive, and in. This is specifically in reference to wheels and road surfaces.
Starting tractive effort, found in the locomotive data sheet, is the rated tractive effort starting from a standstill in run8. Influence of locomotive tractive effort on the wheelrail forces in a curve 024 68 mrad steering angle r 300 m, a lat 1 ms. Note that at high speed, where the air turbulence resistance is very high, the tractive effort is by necessity low. Nov 18, 2006 difference between traction and tractive force. Some graphical solutions of electric railway problems.
But as i said, when you measure both at the same point, horsepower is speed times tractive effort divided by 375, with no qualifications. Dynamic tracking of osteoblastic cell traction force during guided. With the three cylinder locos the nsw d5758 class had that, the tractive effort was, d57 class. Physically the tractive effort in the railwheel contact finno equals the the sum of all acting forces fw resistance on a train. The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. An extended creep force model for large creep applications. 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. For design purposes, usable locomotive tractive effort should not exceed w4, where w is. Since the data files were recorded for any periods of continuous engine operation, these. 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. If you measure tractive effort at the wheel rim, and horsepower somewhere else, then you have to estimate the losses between those two locations. The comprehensiveness of the model rfp is to assist sea staff avoid forgetting important components.
The speed at which both forces are equal is the maximum speed. Horsepower and tractive effort the idiots guide to. Tractive effort definition of tractive effort by merriam. I am moderately curious why my sd75 will let one wheel set slip continuously when i am making a hard pull up the hill. In the chart the plot with shows the results obtained from tractive effort measured by the coupler of type df200 and acceleration of the train. As used in mechanical engineering, the term tractive force can either refer to the total traction a. 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. Jun, 20 hello this is my last questions i have to finish the year, the problem im having is finding the correct way to work it out. Tractive effort using dalemberts principles physics forums. For example, a 3000 hp locomotive will have approximately 74,000 lbs. Locomotives engine and tender weighed 330 tons in working order. Homework statement a vehicle of mass 750kg accelerates up an incline of 1 in 10.
Trip time is assumed to be 120 sec and track length is 2 km trip 3. Nov 21, 2016 1 according to the formulas, it doesnt look like a locomotives tractive effort matters in its acceleration calculation. Total tractive effect required for accelerating the train on a level track. For all cases where only the total force of a vehicle is of importance, an innovative tractive effort method patent pending has been invented at the research and technology centre munich of the deutsche bahn. Vehicle dynamics calculation tractive effort of a car. Total tractive effort 7 torque required on the drive wheel the torque that is required on the drive wheel will be the one that the drive motor requires to produce so as to obtain the desired drive characteristics. Is the maximum tractive effort of a vehicle dependent on rolling resistance or the road adhesion. It is the tractive force at the locomotive driving wheels drivers at the. Optimal control of an emu using dynamic programming and. A typical high speed train te versus speed diagram is shown below.
Sep 22, 2006 tractive effort determines how much a locomotive can haul. Tractive effort versus horsepower trains magazine trains. A locomotive with 0 kn of tractive effort and one with 50,000 kn of tractive effort have the same acceleration curve. This is true not only of the steam locomotive, but also of the various. Rr force necessary to overcome rolling resistance lb. Traction can be defined as the friction between a drive wheel and the surface it moves upon. Dieselelectric traction has the following advantages. It was recommended that for indicated 1932, the author developed constants for a new m ethod of figuring horsepower and tractive effort of steam locom o. Power is the force needed to run a train at a certain speed. Automotively speaking, tractive effort refers to the force, either required or available, provided by the drivetrain or, less commonly, brakes to overcome all resistance factors rolling resistance, wind resistance, grade, drawbar pull, etc.
When moving up in the slope the drive has to produce tractive effort to overcome the force due to gravity. Traction and curving are the principal causes of high tangential forces between railway rails and wheels. This will effect both acceleration and the ability to hill climb. I can find definitions of traction but nothing really on tractive force. These terms apply to different operating conditions, but are related by common mechanical factors. The tractive force ft in the contact area between the tires of the driven wheels and the. Tractive efficiency te, usually thought of as percent but used as a ratio in this paper. Five dimensionless parameters are used to describe tractive performance. Bachmann locos class 20, 37 and 66 vitrains class 37 pulling force one couplers all data are in metric grams. Help with tractive efforthorsepower page 5 railroad. In other words, it is the sum of the tractive force and rolling effort on the road surface. Assessment rfp development toolkit introduction to the toolkit 2 resource from which sea staff can pick and choose what is applicable to their programs, ignoring the rest. Minimalenergy driving strategy for highspeed electric train. The higher your speed, the lower your locomotives tractive effort.
They calculate power by reading the tractive effort whats on the rhs of the sheet. Effect of design parameters on the performance of rigid. Is the maximum tractive effort of a vehicle dependent on. Calculation of the traction effort of switching locomotive. Locomotive model a7 wheel arrangement coco engine emd16567c wheel diameter 1016mm maximum gross power 1450kw1950hp alternator engine rpm 275 835 traction motors emd d77 lube oil capacity 490l control system cooling water capacity 555l air brake b7 continuous tractive effort 239kn dynamic brake fitted. In fact, this type of engine may now be said to be standard on the north.
As thork said, the power rating gives you the resulting calculation for a train based on the empty running weight. 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. Net traction ratio ntr, sometimes called pullweight ratio. A dyno sheet usually wont have a direct conversion to nm on it.
Horsepower x 308 speed mph where 308 is 82% of 375 lbmiles per hour per hp. To do this we will use the maximum tractive effort calculated in equation 9 which was 100 lbs. The tractive effort of any locomotive is speed dependent and can be expressed with a table, a graph or a formula. Professor, biological systems engineering, virginia tech, blacksburg, virginia the primary purpose of agricultural tra ctors, especially those in the middle to high power ranges, is to perform drawbar work. Help with tractive effort horsepower page 5 railroad. Maximum tractive or braking effort is obtained if each powered wheel of the vehicle is rotting at such an angular velocity that its actual peripheral speed is slightly.
I run a lot of time freight trains as i share tracks with passenger trains. Tractive effort determines how much a locomotive can haul. Acceleration is a measure of how quickly you are gaining or losing speed. Gradient modelling with calibrated train performance models. Regardless of locomotive power, usable tractive effort is always limited by wheel rail adhesion. Dec 27, 2017 tractive effort is the ability of the locomotive to transfer power from the engine to the tracks. Tractive effort of steam locomotives locomotive ratiosii by a. The tractive effort required to overcome the force due to gravity. For a given tractive effort, increased horsepower allows an increased speed with other things remaining the same. At 20 nn traction force, the typical displacement on top of the micropost was found to be 2. In that case however, high discretization on the control variable is needed. I need to know exactly what the difference is between traction and tractive force. What links here related changes upload file special pages permanent link page. An extension of the fast method for calculation of creep forces presented in the next chapter allows to adapt the creep force model for various conditions of wheelrail contact according to measurements.
When i have a passenger engine high speed, low te pulling cars of goods, i have to use tricks like not using sharp curves, keeping as many tiles as possible between elevation changes to give the train time to regain speed and keeping congestion down so there isnt a lot of start. Creep forces in simulations of traction vehicles running on. Calculating tractive effort page 1 locomotives and. 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 of steam locomotives locomotive ratiosii. The tractive efficiency of a traction wheel is defined as te output power input power which can be expressed as te pv pv 4 to t vrr where v actual wheel velocity. W u ur tte r f wheel 6 w torque r f friction factor that account for frictional losses between bearings, axles etc.
Influence of locomotive tractive effort on the forces between. 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. Tire mechanics equates it to coulombs friction force which is dependent on road adhesion. Tractive effort is defined as the force at the rims or the outer edges of the driving wheels of moving trains. It is the amount of force a wheel can apply to a surface before it slips.
To convert this to engine torque, you need the following calculation. Tractive effort, curving and surface damage of rails. Ive looked at others but there their problem has differences and what units to use. By dividing both numerator and denominator by wheel load and substituting vvt 1 i, equation 4 reduces to. First, a force of 2 to 5 pounds per ton of train weight is. Tractive effort is the ability of the locomotive to transfer power from the engine to the tracks.
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. For slopes, you will need an additional 100 newton per percent of steepness. Cylinders 23 x 28 drivers 80 boiler pressure 275 lbs. Resistances, tractive effort, and alignment2500 tons of freight have to be moved by rail in conventional rail cars from city a to city b along the rail route shown below using dieselelectric locomotives 3000 gross hp.
Since its a direct force, without any direction, its only measured in newtons. In 4, train motion was formulated in the form of kinetic energy, and a parameterized optimal control effort was derived via the mp. The maximum permissible traction force that can be applied to the wheels is governed by two things. The backbone of train simulation physics is the simple equation, fma force mass x acceleration. Traction effort of switching locomotive chme3 with railroad slope 5.
Influence of locomotive tractive effort on the forces. Oct 06, 2016 if you measure tractive effort at the wheel rim, and horsepower somewhere else, then you have to estimate the losses between those two locations. Locomotive tractive effort and power calculations tractive effort calculations. The term tractive effort is often qualified as starting tractive effort, continuous tractive effort and maximum tractive effort. Retired, john deere product engineering center, waterloo, iowa robert d. Innovative method for measuring the tractive effort of rail.
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