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Strategies for less motion sickness on tilting trains
KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles.
2010 (English)In: Proceedings of Comprail 2010, Southampton: WIT Press , 2010, 581-591 p.Conference paper, Published paper (Other academic)
Abstract [en]

Many railways have put tilting trains into operation on lines with horizontal curves with small radii. Tilting trains have vehicle bodies that can roll inwards, reducing the lateral acceleration perceived by the passengers. Tilting trains can therefore run through curves at higher speeds. However, excessive tilt motions can cause motion sickness in sensitive passengers. On the other hand, too little tilting will cause discomfort from high lateral acceleration and jerk [1].

The present paper presents new tilt algorithms aimed at balancing the conflicting objectives of ride comfort and less motion sickness. An enhanced approach is taken, where the amount of tilt depends on the local track conditions and the train speed. The paper shows how selected tilt algorithms influence certain motion sickness related carbody motions.

Speed profiles designed to avoid local peaks in the risk of motion sickness are another possibility. The speed profiles for both tilting and non-tilting trains are today set from safety and comfort perspectives only, thus minimizing the running time. The present paper shows how speed profiles could be used to balance the conflicting objectives of running time and less risk of motion sickness. The result is derived from simulations and put in relation to today’s tilt algorithms and speed profiles on the Stockholm – Gothenburg main line in Sweden (457 km).

Place, publisher, year, edition, pages
Southampton: WIT Press , 2010. 581-591 p.
Series
WIT Transactions on the Built Environment, ISSN 1746-4498
Keyword [en]
tilting train, tilt algorithm, tilt strategy, passenger comfort, motion sickness, running time simulation
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
URN: urn:nbn:se:kth:diva-33075DOI: 10.2495/CR100541ISI: 000303780200054Scopus ID: 2-s2.0-78649401443ISBN: 978-1-84564-468-0 (print)OAI: oai:DiVA.org:kth-33075DiVA: diva2:413216
Conference
12th International Conference on Computer System Design and Operation in the Railway and other Transit Systems
Note

QC 20110428

Available from: 2011-04-28 Created: 2011-04-28 Last updated: 2012-08-24Bibliographically approved
In thesis
1. Tilting trains: Enhanced benefits and strategies for less motion sickness
Open this publication in new window or tab >>Tilting trains: Enhanced benefits and strategies for less motion sickness
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Carbody tilting is today a mature and inexpensive technology that allows higher train speeds in horizontal curves, thus shortening travel time. This doctoral thesis considers several subjects important for improving the competitiveness of tilting trains compared to non-tilting ones. A technology review is provided as an introduction to tilting trains and the thesis then focuses on enhancing the benefits and strategies for less motion sickness.

A tilting train may run about 15% faster in curves than a non-tilting one but the corresponding simulated running time benefit on two Swedish lines is about 10%. The main reason for the difference is that speeds are set on other grounds than cant deficiency at straight track, stations, bridges, etc. The possibility to further enhance tilting trains’ running speed is studied under identified speed limitations due to vehicle-track interaction such as crosswind requirements at high speed curving. About 9% running time may be gained on the Stockholm–Gothenburg (457 km) mainline in Sweden if cant deficiency, top speed, and tractive performance are improved compared with existing tilting trains. Non-tilting high-speed trains are not an option on this line due to the large number of 1,000 m curves.

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. Scientists have tried to find models that can describe motion sickness based on one or more motion quantities. The vertical acceleration model shows the highest correlation to motion sickness on trains with active tilt. However, vertical acceleration has a strong correlation to several other motions, which precludes vertical acceleration being pointed out as the principal cause of motion sickness in tilting trains.

Further enhanced speeds tend to increase carbody motions even more, which may result in a higher risk of motion sickness. However, means to counteract the increased risk of motion sickness are identified in the present work that can be combined for best effect. Improved tilt control can prevent unnecessary fluctuations in motion sickness related quantities perceived by the passengers. The improved tilt control can also manage the new proposed tilt algorithms for less risk of motion sickness, which constitute one of the main achievements in the present study. Local speed restrictions are another means of avoiding increased peak levels of motion sickness when increasing the overall speed.

The improved tilt control and the proposed tilt algorithms have proven to be effective in on-track tests involving more than 100 test subjects. The new tilt algorithms gave carbody motions closer to non-tilting trains. Rather unexpectedly, however, the test case with the largest decrease in tilt gave a greater risk of motion sickness than the two test cases with less reduction in tilt. It is likely that even better results can be achieved by further optimization of the tilt algorithms; the non-linear relation between motions and motion sickness is of particular interest for further study.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. vi, 36 p.
Series
Trita-AVE, ISSN 1651-7660 ; 2011:26
Keyword
tilting trains, running time, ride comfort, motion sickness, tilt control
National Category
Vehicle Engineering
Research subject
Järnvägsgruppen - Gröna tåget
Identifiers
urn:nbn:se:kth:diva-33077 (URN)978-91-7415-948-6 (ISBN)
Public defence
2011-05-19, D3, Lindstedtsvägen 5, KTH, Stockholm, 09:30 (English)
Opponent
Supervisors
Funder
TrenOp, Transport Research Environment with Novel Perspectives
Note
QC 20110429Available from: 2011-04-29 Created: 2011-04-28 Last updated: 2012-06-12Bibliographically approved

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CiteExportLink to record
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Citation style
  • apa
  • harvard1
  • ieee
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Output format
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