UIC comfort tests - VTI

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1 Summary1.1 Requirements1.1.1 HistoryThe ERRI B153 committee undertook a number of studies on ride comfort, butalways comfort (seated and standing) on mainly straight track. Therefore theconclusions from this work (N VA and N MV ) cannot be used without verification fora journey on a track with a high number of curves. Extrapolation from multipleregression analysis is not allowed.The CEN standard (ENV 12299:1999) includes procedures for the evaluationof local comfort on curve entry transitions (P CT ) and at discrete events on circularcurves (P DE ). However, the conditions in normal commercial operation are suchthat these measures do not give convincing results because the level of theaccelerations is not sufficiently high.The ERRI B207 committee carried out ride comfort tests on curved track, butthe results were inconclusive due to problems with the test data.1.1.2 Situation before the now completed tests• The existing procedures N VA and N MV are not applicable on track containing arelatively high number of curves.• The P DE and P CT methods deal only with local comfort and are only valid in arelatively high acceleration environment.1.1.3 Remaining requirementsSpecialists were convinced that the following research should be done:• Study of local comfort in circular curves and curve transitions, in order toguide the construction of track and trains.• Study of the average comfort on track with a high number of curves in order tobe able to appreciate the global influence of different track and vehicleparameters on comfort.• Study of the provocation of nausea, phenomena that limit the full use of thecapabilities of tilting trains.1.2 Origin of the workThe work was first proposed by the high-speed division of UIC, and taken over bythe working group "Improvement of passenger train performance on conventionallines". The idea was that it should be possible to improve the commercial speedon a given line, without too much investigation. One possibility was to increasethe speed in curves without taking any other action, which will increase the lateralacceleration experienced by the passengers. Increasing the cant in circular curveswas also a solution, using tilting train bodies was a supplementary possibility.What are the supplementary constraints on the passengers? The centrifugal forcesare more balanced during the ride on the circular curve, but in the transition, anumber of phenomena appear, and degrade comfort. On some occasions we knowthat onset of nausea can occur.The original testing procedure proposed by the working group asked forexperiments in two countries, but this was so expensive that UIC could not agreewith the proposal. As a compromise UIC agreed with one test series on a carefullyVTI notat 56A-2003 9
chosen test track with a minimum of test persons. Numerical simulations shouldfacilitate the choice. However it is clear that while simulation helps to a certainextent, the consequences of this choice inevitably reduce the robustness of theresults.1.3 Preparation of the tests1.3.1 Characteristics of the potential participating trainsThree companies were asked to deliver numerical characteristics of the mostrecent trains in service, under strictly confidential conditions, to allow theworking group to undertake simulations as a preparation for the tests.One manufacturer refused, a second manufacturer delivered rather generalcharacteristics. A last manufacturer delivered an add-on module, to makesimulation possible. Because of the attitude of the first manufacturer, theremaining possibilities of test journeys were reduced to two administrations.1.3.2 Results of the simulationTwo series of simulations were executed, giving information on the roll speed, thejerk and the lateral acceleration on the passenger on each of the two remaining testjourneys. The results were sufficiently accurate for choosing an appropriate testtrack, but not for the forecasting of the comfort, as some essential informationwere not present in the furnished models.Both of the proposed test journeys were acceptable. Considering both theavailability of data and constraints on the availability of the test train, the journeyFirenze-Arezzo from FS-Trenitalia was chosen as the solution.A second series of simulations with the proposed test train on this journey wasused to guide the selection of local events to be evaluated on each test run, inorder to assure the largest possible experimental basis for the statistical analysis ofthe tests. 15 simple curve entry transitions and 9 plain curves were chosen,together with some other kinds of transition (4 reverse transitions, 4 adjacenttransitions, 3 compound transitions and 1 short curve). The results of the testconfirmed the choices made.1.3.3 Test planTesting was planned to last for one week. Two days were needed for tests of localcomfort and two days for the evaluation of average comfort. One spare day wasplanned to allow any failed tests to be repeated or to execute complementarysituations.The journey firenze-arezzo-firenze was to be executed two times a day. Thiswould give a maximum of 15 transitions * 2 days * 2 directions* 2 runs * 5groups = 600 data cases for local comfort, and 8 five-minute zones * 2 days * 2runs * 2 directions = 64 independent data cases for average comfort.1.4 Execution of the testsThe tests were executed as planned.This test plan proved sufficient for local comfort. For the evaluation of averagecomfort, it was found that the chosen test plan gave only a minimal number ofdata cases. The exclusive use of good track and good quality coaches resulted in arather small spread of input data, making it difficult to obtain good regressions.10 VTI notat 56A-2003
Page 1 and 2: VTI notat 56A • 2003VTI notat 56A
Page 3 and 4: ContentsPageAbbrivations and Notati
Page 5 and 6: 10.5.1 Transitions 5311 Evaluation
Page 7: Abbrivations and NotationsAEAT AEA
Page 11 and 12: 1.8.2 ModelsThree different models
Page 13 and 14: 3 What does comfort mean in the con
Page 15 and 16: Representation of passengers’ opi
Page 17 and 18: 4 How comfort evolves with speed4.1
Page 19 and 20: Each element may provoke a potentia
Page 21 and 22: 5.2.2 Theoretical behaviour of thos
Page 23 and 24: Nominal acceleration in the horizon
Page 25 and 26: 6 Actual evaluation rulesAll the fo
Page 27 and 28: Important variancesS 0 = var(y)Sr =
Page 29 and 30: 7 Choice of the test zone7.1 Choice
Page 31 and 32: 9.008.007.006.00roll velocity5.004.
Page 33 and 34: 8 Description of the test8.1 The tr
Page 35 and 36: 8.3.3 Synchronisation between votes
Page 37 and 38: 8.5 Registration of data, calculati
Page 39 and 40: DRIVER CAB8.6.2 Occupied places2224
Page 41 and 42: 9.3 Study of the car body angle9.3.
Page 43 and 44: 9.4.2 Influence of length of the co
Page 45 and 46: 9.4.4 Additional discomfort due to
Page 47 and 48: 10.1.1 ConclusionsThe actual distri
Page 49 and 50: 10.3 Seat positionThe influence of
Page 51 and 52: Average votes for the different tra
Page 53 and 54: Figures 10-5 to 10-10 show the infl
Page 55 and 56: Influence by roll velocity on voteA
Page 57 and 58: 5.0Influence by Pct on voteAll cate
Page 59 and 60:
11 Evaluation of local comfort11.1
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11.1.4 Scaling of votesThe N’ VA
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Note that very high values of later
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554433N'vaN'va221100 1 2 3 4Lateral
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Multiple regressions have therefore
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With the 1.0-second window, the jer
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The regression has been repeated wi
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(Table 11-12)Object: Simple and adj
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simple transitions, and with the re
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Table 11-18 Regression for track en
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Some characteristic data points of
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The probability that all coefficien
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Second conclusionThis also proves t
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number of real votes3025201510500,2
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11.2.2 ParametersFour parameters we
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There are some observations from th
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Table 11-30 Two-parameter regressio
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Three-parameter regression - N'VA,
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The three-parameter regression was
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12 Evaluation of average comfort12.
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Table 12-2 shows that the correlati
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3.53.5332.52.5NVA21.5NVA21.5110.50.
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Table 12-5 Multiple regression for
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This is the preferred result to be
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12.2.5 Density of importance of eac
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13.3 Conclusions in relationship wi
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An identical observation can be mad
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13.7.3 Evaluation of local comfort
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Appendix 1Page 1 (3)1 Preparing the
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Appendix 1Page 3 (3)2.5 Publish res
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Appendix 2Page 2 (10)For this progr
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Appendix 2Page 4 (10)Vertical accel
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Appendix 2Page 6 (10)Influence of l
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Appendix 2Page 8 (10)Red line : 0.1
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Appendix 2Page 10 (10)Study of aver
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Appendix 3Page 2 (2)Evaluation of h
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UIC comfort tests - VTI

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