On enhanced tilt strategies for tilting trains

Kufver, Björn; Persson, Rickard

doi:10.2495/cr060821

Cited by 5 publications

(5 citation statements)

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“…Further reduction in motion difference between tilting and non-tilting trains can be achieved by letting the local track geometry influence the (variable) compensation factor. This was first mentioned in [11] and further developed to reduce the risk of motion sickness in [12,13]. The variable compensation factor led to an enhanced approach, where the tilt angle as a function of train speed was calculated for each curve in advance.…”

Section: Tilt Reference For Reduced Risk Of Motion Sicknessmentioning

confidence: 99%

On-track test of tilt control strategies for less motion sickness on tilting trains

Persson

Kufver²,

Berg

2012

Vehicle System Dynamics

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Carbody tilting is today a mature and inexpensive technology that permits higher train speeds in horizontal curves, thus shortening travel time. However, tilting trains run a greater risk of causing motion sickness than non-tilting ones. It is likely that the difference in motions between the two train types contributes to the observed difference in risk of motion sickness. Decreasing the risk of motion sickness has until now been equal to increasing the discomfort related to quasi-static lateral acceleration. But, there is a difference in time perception between discomfort caused by quasi-static quantities and motion sickness, which opens up for new solutions. One proposed strategy is to let the local track conditions influence the tilt and give each curve its own optimised tilt angle. This is made possible by new tilt algorithms, storing track data and using a positioning system to select the appropriate data. The present paper reports from on-track tests involving more than 100 test subjects onboard a tilting train. A technical approach is taken evaluating the effectiveness of the new tilt algorithms and the different requirements on quasi-static lateral acceleration and lateral jerk in relative terms. The evaluation verifies that the rms values important for motion sickness can be influenced without changing the requirements on quasi-static lateral acceleration and lateral jerk. The evaluation shows that reduced quantities of motions assumed to have a relation to motion sickness also lead to a reduction in experienced motion sickness. However, a limitation of applicability is found as the lowest risk of motion sickness was not recorded for the test case with motions closest to those of a non-tilting train. An optimal level of tilt, different from no tilt at all, is obtained. This non-linear relation has been observed by other researchers in laboratory tests.

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Section: Tilt Reference For Reduced Risk Of Motion Sicknessmentioning

confidence: 99%

On-track test of tilt control strategies for less motion sickness on tilting trains

Persson

Kufver²,

Berg

2012

Vehicle System Dynamics

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“…However, such curves constitute only about 15 per cent of the total number of curves on the line between Stockholm and Gothenburg. For many of the remaining 85 per cent of the curves, it is possible to reduce the tilt angle compared with the tilt applied today [24]. On many of these curves, it is even possible to keep the vertical acceleration unchanged without exceeding limits on comfortable lateral carbody acceleration.…”

Section: Quantification Of Motions Due To Enhanced Speedmentioning

confidence: 99%

Tilting Trains: Benefits and Motion Sickness

Persson

2010

Proceedings of the Institution of Mechanical Engineers, Part F:

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Carbody tilting is today a mature and inexpensive technology that allows higher speeds on curves, thus shortening travel time. The technology has been accepted by many train operators, but some issues are still holding back the full potential of tilting trains. This paper focuses on improving the benefits and limiting the drawbacks of tilting trains. This is done by quantifying the possible running time benefits compared with today's tilting trains, identifying what motion components have an influence on motion sickness, and finally quantifying the influence from the increased speed on these motion components. A running time analysis was made to show what potential there is to further improve running times by optimizing tracks and trains. Relations between cant deficiency, top speed, tractive performance, and running times are shown for a tilting train. About 9 per cent running time may be gained on the Stockholm-Gothenburg (457 km) main line in Sweden if cant deficiency, top speed, and tractive performance are improved compared with existing tilting trains. Introduction of non-tilting high-speed trains is not an option on this line due to the large number of 1000 m curves. However, tilting trains run a greater risk of causing motion sickness than non-tilting trains. Roll velocity and vertical acceleration are the two motion components that show the largest increase, but the amplitudes are lower than those used in laboratory tests that caused motion sickness. Higher curve speeds will increase carbody motions still further, but there are some possibilities to trade between vertical and lateral carbody acceleration by increasing or decreasing roll.

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“…In practice, the length of transition curves at different railways are usually determined using empirical methods and equations based on available codes and standards. According to the available literature, 2,3 although the variation of the lateral acceleration is not highly sensitive to the variation of TCL, variation rate of the lateral jerk has a significant influence on the ride comfort. So, in this research, the optimum length of clothoid transition curve has been investigated with focus on three common parameters that affect the passengers ride comfort in transition curved track including the lateral jerk, vertical acceleration, and the angular rolling velocity.…”

Section: Introductionmentioning

confidence: 99%

Investigation on optimum lengths of railway clothoid transition curves based on passenger ride comfort

Sadeghi

Rabiee

Felekari

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part F:

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Transition curves are considered as inevitable parts of railways. As they tend to bend the train’s course of movement, the passengers ride comfort and safety are strongly challenged. Although many investigations have performed on the dynamic behavior characteristics of transition curves, only a few studies have focused on the optimum transition length based on the ride comfort index. In response to this need, a vehicle-track dynamic model was developed. The results obtained from model were compared with those available in the literature to prove the validity of the model. Through a parametric study, the dynamic responses of a vehicle passing through the transition curves was studied using the model developed in this study. The ride comfort index was obtained using the dynamic response of the vehicle. The lateral jerk, vertical acceleration, and rolling velocity were considered as the dynamic response of the vehicle. The optimum transition curve length for various configurations of curve radius and super-elevation magnitudes were investigated based on the obtained ride comfort.

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On enhanced tilt strategies for tilting trains

Cited by 5 publications

References 0 publications

On-track test of tilt control strategies for less motion sickness on tilting trains

On-track test of tilt control strategies for less motion sickness on tilting trains

Tilting Trains: Benefits and Motion Sickness

Investigation on optimum lengths of railway clothoid transition curves based on passenger ride comfort

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