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268 Acceleration, m/s/s and lateral dynamics. Both standards refer to Australian Standard AS2670 19 stating that vibration in any passenger seat shall not exceed either the “reduced comfort boundary” (RCB), or the “fatigue decreased proficiency boundary” (FDPB), of AS2670 in any axis. So, while not specifying calculations in the railway standards, acriteria for longitudinal comfort can be drawn from the general Australian Standard, AS 2670. Another Australian standard which is useful when considering longitudinal comfort issues is AS3860 (Fixed Guideway People Movers). 20 This standard gives maximum acceleration limits for sitting and standing passengers. It also gives maximum values for “jerk”, the time derivative of acceleration. Ajerk limitslightly lower than the Australian standard AS 3860 of 1.5 m/sec 3 is also quoted byProfillidis. 15 More elaborate treatment of longitudinal comfort was located in the UIC Leaflet 513, Guidelines for evaluating passenger comfort in relation to vibration in railway vehicles, issued 1/11/2003. 21 The UIC approach integrates longitudinal accelerations into asingle parameter. Vertical, lateral, and longitudinal accelerations are measured and weighted with appropriate filters. Rootmean square values of accelerations taken over 5sec time blocks are calculated. The testdata sample is of 5min duration. The 95th percentile point in each event distribution is then used to calculate asingle parameter. The equation for the simplified method (where measurements are Displacement, mm 10 8 6 4 2 0 0 5 10 15 20 100 10 1 0.1 0.01 Frequency, Hz FIGURE 9.42 Passenger comfort acceleration limits. 0 5 10 15 20 Frequency, Hz FIGURE 9.43 Passenger comfort displacement limits. © 2006 by Taylor & Francis Group, LLC Handbook of Railway Vehicle Dynamics 0.3g Limit(ROA) Max. Acc. (Seated AS 3860) Max. Acc. (Standing AS 3860) Max Jerk (Seated AS 3860) Max Jerk (Standing AS 3860) 1Minute Exp.FDPB (AS 2760) 1Minute Exp.RCB (AS 2760) 0.3g Limit (ROA) Max. Acc. (Seated AS 3860) Max. Acc. (Standing AS 3860) Max Jerk (Seated AS 3860) Max Jerk (Standing AS 3860) 1Minute Exp.FDPB (AS 2760) 1Minute Exp.RCB (AS 2760)
Longitudinal Train Dynamics 269 taken on the vehicle floor) is quoted below. ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi N MV ¼ 6 ð a XP95Þ 2 þða YP95Þ 2 þða ZP95Þ 2 q ð 9 : 23Þ where a XP is acceleration in the longitudinal direction; a YP is acceleration inthe lateral direction; and a ZP is acceleration in the vertical direction. Afurther equation isavailable for standing passengers, this time using 50 percentile points from event distributions. ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi N VD ¼ 3 16ð a XP50Þ 2 þ 4 ð a YP50 Þ 2 þða ZP50Þ 2 þ 5 ð a ZP95Þ 2 q ð 9 : 24Þ Ride criteria using the above index parameters is: N , 1: very comfortable; 1 , N , 2: comfortable; 2 , N , 4: medium; 4 , N , 5: uncomfortable; and N . 5: very uncomfortable. VI. TRAIN MANAGEMENT AND DRIVING PRACTICES A . T RAIN M ANAGEMENT AND D RIVING P RACTICES Train management and driving practices has received considerable attention in literature dating back several decades. Technology developments, such as the transitions from steam to dieselelectric locomotives, improved locomotive traction control systems, remote control locomotives, operation ofvery long heavy haul units trains, and the operation of high speed passenger services, have ensured that this area continues to evolve. Train management and driving practices will differ for different rail operations. Suburban train drivers will be motivated primarily by the need to run on time. Asecondary consideration may be energy consumption. Longitudinal dynamics will have minimal consideration as cars are connected with minimal slack and usually have distributed traction and slip controls for both traction and braking. Passenger express services will be similarly motivated. Slow passenger services with locomotive hauled passenger cars will share the concerns of running ontime with the next priority being the smoothness of passenger ride. Passenger train driver practice often includes energy consumptive power braking tominimise slack action. Where locomotives have excess power, train drivers have been known tooperate with aminimum brake application on for several kilometres to reduce slack action over undulations. Mixed freight train practice, while not motivated by passenger comfort, will share some similar driving practices to ensure train stability. This is particularly the case when trains are operated with mixes of empty and loaded wagons. Running on time will be an emphasis on some systems depending on the type of freight. Differing from passenger systems, energy consumption is asignificant freight cost factor and is emphasised in freight operations. The operation of bulk product/uniform module type freight trains (unit trains or blocktrains), e.g., carrying minerals, grain, containers etc, can be optimised to the specific source/destination requirements. In some cases, timeliness is asecondary concern while tonnage per week targets must beachieved. Despite the differences inoperation, acommon thread to train management is the issue of speed control and hence management of train momentum. For suburban passenger trains, speed must be managed to ensure timeliness and adequate stopping distances for signals and for positioning at platforms. For longer locomotive hauled passenger, freight, and heavy haul unit trains, the problem of momentum control becomes even more significant due to the larger masses involved. Ingeneral, itisdesirable to apply power asgradually as possible until in-train slack is taken up. During running it is desirable to minimise braking and energy wastage utilising coasting where possible. Route running schedules will limit the amount of time that the train can coast. Longer trains can coast over undulating track more easily than shorter trains due to grade forces being partially balanced within the train length. Stopping is achieved at several different rates. © 2006 by Taylor & Francis Group, LLC
Page 1 and 2: 9 CONTENTS Longitudinal Train Dynam
Page 3 and 4: Longitudinal Train Dynamics 241 ass
Page 5 and 6: Longitudinal Train Dynamics 243 By
Page 7 and 8: Longitudinal Train Dynamics 245 Pol
Page 9 and 10: Longitudinal Train Dynamics 247 For
Page 11 and 12: Longitudinal Train Dynamics 249 If
Page 13 and 14: Longitudinal Train Dynamics 251 var
Page 15 and 16: Longitudinal Train Dynamics 253 For
Page 17 and 18: Longitudinal Train Dynamics 255 Com
Page 19 and 20: Longitudinal Train Dynamics 257 Tra
Page 21 and 22: Longitudinal Train Dynamics 259 Bra
Page 23 and 24: Longitudinal Train Dynamics 261 The
Page 25 and 26: Longitudinal Train Dynamics 263 G .
Page 27 and 28: Longitudinal Train Dynamics 265 Lon
Page 29: Longitudinal Train Dynamics 267 FIG
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Page 35 and 36: Longitudinal Train Dynamics 273 Res
Page 37 and 38: Longitudinal Train Dynamics 275 ope
Page 39: Longitudinal Train Dynamics 277 V f

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