Safety Assessment for Flange Climb Derailment of Trains Running at Low Speeds on Sharp Curves

Ishida, Hiroaki; Miyamoto, Takefumi; Maebashi, Eiichi; Doi, Hisayo; Iida, K.; Furukawa, Atsushi

doi:10.2219/rtriqr.47.65

Cited by 39 publications

(22 citation statements)

References 2 publications

(2 reference statements)

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“…It is also well known that dynamic reductions of the vertical load on the wheel are extremely unfavourable in terms of derailment, since they cause a reduction in normal force and therefore an increase in the coefficient (L/V) [3,13]. In fact, a reduction in normal force is specially harmful since not only does it increase the value of the coefficient (L/V), but simultaneously reduces the permissible limit (L/V) lim .…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…This has prompted a number of researchers in recent years to establish alternative improved formulae, which take into account not only the friction coefficient and the angle of the flange, but also one or more of the above mentioned factors [10][11][12][13][14][15][16]. These equations attempt to predict more accurately the actual risk of derailment at any given moment.…”

Section: Introductionmentioning

confidence: 99%

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Influence of creep forces on the risk of derailment of railway vehicles

Santamaría

Vadillo

Gómez

2009

Vehicle System Dynamics

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Abstract:The derailment mechanism in a railway vehicle is a complex mechanical phenomenon which has been, and still is, the subject of intense research activity due to the serious consequences it can entail. Since Nadal deduced his well-known formula, many researchers have put forward alternative equations which all attempt to move closer to data obtained experimentally. This paper provides a summary of the best known, and draws up a new formulation based on the theoretical 3-D study of creep forces emerging in contact on the wheel likely to derail. It also provides an in-depth analysis of the role played by spin creepage, including its effect on obtaining theoretical derailment limits which are more realistic than those obtained using Nadal's formula. Finally, a new derailment criteria is proposed. This new criteria leads to less conservative values than Nadal's equation for zero yaw angles. When the yaw angle is high enough, the results obtained are coincident with those predicted by Nadal's equation.

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Section: Discussion Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of creep forces on the risk of derailment of railway vehicles

Santamaría

Vadillo

Gómez

2009

Vehicle System Dynamics

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“…(7). To consider the effect of y on derailment, the friction coefficient µ is replaced with an equivalent expression (f y /N) [12]. (8) where, f y is the lateral creep force, N is the force acting on the contact patch in the normal direction, κ is the lateral creep coefficient, and ε is an index indicating the saturation property of creep force.…”

Section: Derailment Coefficientmentioning

confidence: 99%

“…Here, the vehicle behavior is confirmed in the output animation, and the flange climbing behavior is analyzed using the output data such as wheel lateral force Q and wheel load P and so on. The derailment coefficients, Q/P, are calculated and compared with Nadal's critical derailment coefficient [11] employing an equivalent frictional feature, which is expressed as a non-linear function of the attack angle [12]. The result shows that the critical − 94 − Takahiro Hosoi and Katsuya Tanifuji / IJR, 5(2), 93-101, 2012 derailment coefficients employing the equivalent frictional feature, , become close to the actual derailment coefficients, Q/P, at the timing that flange climbing occurs.…”

Section: Introductionmentioning

confidence: 99%

Effect of Crosswind on Derailment of Railway Vehicles Running on Curved Track at Low Speed

Hosoi¹,

Tanifuji²

2012

International Journal of Railway

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Owing to the lightening of railway vehicles and increased operation speeds, the reduction of running safety in the presence of crosswind is becoming an important problem. In particular, the running safety tends to decrease when vehicles run on curved track. When a crosswind acts on a vehicle negotiating a curve from the outer side, flange climbing can occur. In this study, a full-vehicle model was constructed using the multi-body simulation software SIMPACK, and a simulation of a bogie vehicle with two-axle trucks negotiating a curve was carried out to examine the running safety under the condition where a crosswind acts on the vehicle from the outer side of the curve. As a result, it was verified that the derailment coefficient of the first wheelset becomes large in the exit transition curve and the coefficient of the third wheelset does in the entrance transition curve, and this trend becomes pronounced at low operation speeds in the presence of a stronger crosswind. It was also shown that the critical derailment coefficients obtained by modified Nadal's formula considering the effect of attack angle become close to the actual derailment coefficients at the timing that flange climbing occurs.

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“…In the same way, various publications presenting the results of several dynamic simulations in which the value of some parameters related to the wheel-rail contact , dealing with safety studies can be found in: (27), (28), (29), (30), (31), (32), (33), (34), (35), (36), (37), (38), (39), (40), (41), (42), (43), (44), (45), (46), (47), (48), (49), (50), (51), (52), (53), (54) and (55); some others dealing with track fatigue studies can be found in: (51), (52), (56) and (57); and some dealing with ride quality studies in: (58) and (59) .…”

Section: Introductionmentioning

confidence: 99%

Influence of the track quality and of the properties of the wheel–rail rolling contact on vehicle dynamics

Suarez

Félez

Lozano

et al. 2013

Vehicle System Dynamics

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This work describes an analytical approach to determine what degree of accuracy is required in the definition of the rail vehicle models used for dynamic simulations. This way it would be possible to know in advance how the results of simulations may be altered due to the existence of errors in the creation of rolling stock models, whilst also identifying their critical parameters. This would make it possible to maximize the time available to enhance dynamic analysis and focus efforts on factors that are strictly necessary.In particular, the parameters related both to the track quality and to the rolling contact were considered in this study. With this aim, a sensitivity analysis was performed to assess their influence on the vehicle dynamic behaviour. To do this, 72 dynamic simulations were performed modifying, one at a time, the track quality, the wheel-rail friction coefficient and the equivalent conicity of both new and worn wheels. Three values were assigned to each parameter, and two wear states were considered for each type of wheel, one for new wheels and another one for reprofiled wheels.After processing the results of these simulations, it was concluded that all the parameters considered show very high influence, though the friction coefficient shows the highest influence. Therefore, it is recommended to undertake any future simulation job with measured track geometry and track irregularities, measured wheel profiles and normative values of wheel-rail friction coefficient. This is an electronic version of an article published in Vehicle

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Safety Assessment for Flange Climb Derailment of Trains Running at Low Speeds on Sharp Curves

Cited by 39 publications

References 2 publications

Influence of creep forces on the risk of derailment of railway vehicles

Influence of creep forces on the risk of derailment of railway vehicles

Effect of Crosswind on Derailment of Railway Vehicles Running on Curved Track at Low Speed

Influence of the track quality and of the properties of the wheel–rail rolling contact on vehicle dynamics

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