A Re-Examination of the Proneness to Derailment of a Railway Wheel-Set

Gilchrist, Alasdair; Brickle, Barrie

doi:10.1243/jmes_jour_1976_018_023_02

Cited by 37 publications

(12 citation statements)

References 7 publications

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“…As the lateral force increases the potential for flange climbing where the wheel rides up the flange onto the rail head is increased, conversely an increase in the vertical force at this wheel reduces this possibility. Both of these factors are included in the derailment quotient and a limit can be calculated based on the coefficient of friction and flange angle using a simple method first outlined by Nadal and described by Gilchrist and Brickle [23]. The practical limit for the derailment quotient in most cases is between 1 and 1.2.…”

Section: Assessment Of Vehicle Behaviourmentioning

confidence: 99%

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Integration of Crosswind Forces into Train Dynamic Modelling

Baker

Hemida

Iwnicki

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part F:

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Abstract:In this paper a new method is used to calculate unsteady wind loadings acting on a railway vehicle. The method takes input data from wind tunnel testing or from computational fluid dynamics simulations (one example of each is presented in this article), for aerodynamic force and moment coefficients and combines these with fluctuating wind velocity time histories and train speed to produce wind force time histories on the train. This method is fast and efficient and this has allowed the wind forces to be applied to a vehicle dynamics simulation for a long length of track.Two typical vehicles (one passenger, one freight) have been modelled using the vehicle dynamics simulation package 'VAMPIRE ® ', which allows detailed modelling of the vehicle suspension and wheel-rail contact. The aerodynamic coefficients of the passenger train have been obtained from wind tunnel tests while those of the freight train have been obtained through fluid dynamic computations using large-eddy simulation. Wind loadings were calculated for the same vehicles for a range of average wind speeds and applied to the vehicle models using a user routine within theVAMPIRE package. Track irregularities measured by a track recording coach for a 40 km section of the main line route from London to King's Lynn were used as input to the vehicle simulations.The simulated vehicle behaviour was assessed against two key indicators for derailment; the Y /Q ratio, which is an indicator of wheel climb derailment, and the Q/Q value, which indicates wheel unloading and therefore potential roll over. The results show that vehicle derailment by either indicator is not predicted for either vehicle for any mean wind speed up to 20 m/s (with consequent gusts up to around 30 m/s). At a higher mean wind speed of 25 m/s derailment is predicted for the passenger vehicle and the unladen freight vehicle (but not for the laden freight vehicle).

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Section: Assessment Of Vehicle Behaviourmentioning

confidence: 99%

“…• value was taken as 1.15, while for the lift force coefficient, the value was taken as 0.8, which gives the best fit to the data over the yaw angle range of most interest (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) • ). These tests were also used to obtain values of the aerodynamic weighting function.…”

Section: Class 365mentioning

confidence: 99%

Integration of Crosswind Forces into Train Dynamic Modelling

Baker

Hemida

Iwnicki

et al. 2011

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…N is the maximum available force. Using equation (2), the region of smaller L/V (0<L/V<0.66) in Figure 4 would require a theoretical value of F tan (theoretical) ≥ µ . N for equilibrium.…”

Section: Climbing and Sliding Characteristicsmentioning

confidence: 99%

“…This relationship leads to the Nadal limit for the prediction of the onset of wheel climb. The difficulty of completely understanding wheel climb is illustrated by the large number of papers that have been written on this subject through the years including Gilchrist and Brickle [2], Weinstock [3], Elkins and Shust [4], [5] and Blader [6], [7]. It should be noted that the Nadal limit is accurate for high angle of attack (AOA) conditions associated with F tan > F long , as the wheelset rolls forward in quasi-static steady motion leading to a flange climbing scenario.…”

Section: Introductionmentioning

confidence: 99%

Application of Nadal Limit for the Prediction of Wheel Climb Derailment

Marquis

Greif

2011

2011 Joint Rail Conference

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Application of the Nadal Limit to the prediction of wheel climb derailment is presented along with the effect of pertinent geometric and material parameters.Conditions which contribute to this climb include wheelset angle of attack, contact angle, friction and saturation surface properties, and lateral and vertical wheel loads. The Nadal limit is accurate for high angle of attack conditions, as the wheelset rolls forward in quasi-static steady motion leading to a flange climbing scenario. A detailed study is made of the effect of flange contact forces F tan and N, the tangential friction force due to creep and the normal force, respectively. Both of these forces vary as a function of lateral load L. It is shown that until a critical value of L/V is reached, climb does not occur with increasing L since Ftan is saturated and the flange contact point slides down the rail. However, for a certain critical value of L/V (i.e. the Nadal limit) F tan is about to drop below its saturated value and flange climb (rolling without sliding) up the rail occurs. Additionally, an alternative explanation of climb is given based on a comparison of force resultants in track and contact coordinates.

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“…However, in 1976, Gilchrist and Brickle [2] reviewed the Nadal derailment evaluation criterion according to the Hertz contact theory and Duvorol creep force table, pointing out that it, to a certain extent, was conservative under small wheel-rail attack angles and agreed that the Nadal derailment evaluation criterion was appropriate in evaluating derailment under large wheel-rail attack angles. Sweet and Karmel [3][4][5] simulated wheel derailment under quasistatic assumption according to the two-degree-of-freedom (2-DOF) and threedegree-of-freedom (3-DOF) dynamic wheelset derailment models and obtained consistent results compared with those of the 1 : 5 single wheelset derailment model test.…”

Section: Introductionmentioning

confidence: 99%

Theoretical 3D Model for Quasistatic Critical Derailment Coefficient of Railway Vehicles and a Simplified Formula

Wang

et al. 2018

Mathematical Problems in Engineering

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The formula for the critical derailment coefficient concerning wheelset yaw angles and wheel-rail creep forces is deduced based on the three-dimensional (3D) force equilibrium relationship in the critical wheel derailment state under quasistatic assumption. The change of critical derailment coefficient and wheel-rail contact patch normal force/creep force as wheelset yaw angles change under the influence of the friction coefficient, maximum flange angle, and net wheel weight is analyzed according to the Kalker linear creep theory and Shen-Hedrick-Elkins creep theory. Analysis shows that the wheel-rail friction coefficient and maximum wheel flange contact angle can significantly influence the critical wheel derailment coefficient, further proving the conservative results when the critical Nadal derailment coefficient is adopted in analyzing wheel derailment under small wheelset yaw angles. To realize easy calculation and application of critical 3D derailment coefficients, the ratio of lateral creep force to longitudinal creep force of wheel-rail contact patches under critical quasistatic wheel derailment conditions is deduced. A simplified calculation method of critical derailment coefficients is presented based on this. The calculation accuracy is verified, proving that it can satisfy engineering application.

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A Re-Examination of the Proneness to Derailment of a Railway Wheel-Set

Cited by 37 publications

References 7 publications

Integration of Crosswind Forces into Train Dynamic Modelling

Integration of Crosswind Forces into Train Dynamic Modelling

Application of Nadal Limit for the Prediction of Wheel Climb Derailment

Theoretical 3D Model for Quasistatic Critical Derailment Coefficient of Railway Vehicles and a Simplified Formula

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