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52 APPENDIX A TCRP Research Project C-16 Scope of Work The research was organized into 11 tasks as follows: within which they will be used, especially conditions that apply on U.S. and Canadian light rail systems. Phase 1-- The extent to which issues have arisen internationally, how they have been dealt with, and how successful any correc- Task 1. Review of domestic and international literature. tive measures have been. Task 2. Collection of information from suppliers and tran- Comparing conditions that may have caused issues inter- sit systems. nationally with those that exist in the United States and Task 3. Identification of the factors contributing to per- Canada. formance issues. Finding data on wheel and rail wear where center trucks of Task 4. A working paper covering Tasks 1 through 3. this type have been used. Task 5. Identification and planning of the research needed Finding out how vehicle manufacturers have responded to in Phase 2. these issues and seeing if they have modified their designs. Task 6. Production of the interim report covering Tasks 1 Establishing if standards in the United States differ from through 5. other countries using these vehicles, and whether such dif- ferences might contribute to any known issues or might Phase 2-- limit the potential for corrective action. Task 7. Execution of the approved research plan. Obtaining details of the history of performance issues in Task 8. Production of a working paper summarizing the order to identify any patterns. results of Task 7. Reviewing the documentation of vehicle and/or track Task 9. Development of the guidance required to mitigate modifications implemented by transit systems in order to performance issues. address the issues. Task 10. Development of recommendations for further research. It was thought that the best material would be that pro- Task 11. Development of the final report. duced by the transit authorities and vehicle manufacturers themselves. Documents that report on these organizations' The notes that follow describe the work carried out on each activities will tend to be prone to error, and previous research task. Conclusions and results are summarized; text in the and periodical articles based on second-hand reports will, in body of the report is not duplicated. turn, be even more likely to be inaccurate. A "hierarchy" of documents in terms of their reliability was created in order to avoid this issue. Task 1. Literature Review The literature review was carried out by a team of engineers The review focused on locating information as early as pos- and technical specialists in this area working internationally sible that illuminated the following issues: and sharing information continually via email. Interfleet assessed literature using a form developed for The principles applied in designing vehicles. this purpose. The form was used to record the essential The extent to which the designs of center trucks and vehi- information, providing a summary in English that could cle articulation have taken into account the environment easily be referred to at any stage in the project. The form was

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53 also designed so that the data could be recorded in data base telephone and email contacts. Although this and the preced- format. ing tasks targeted partial low-floor vehicles of a specific The overall view was that the amount of literature that is design, where appropriate, the experience of operators of directly relevant and of high value to this research was fairly 100-percent low-floor cars was also taken into account. This limited and that the main pieces of literature had probably was done to estimate whether there were lessons to be learned been identified and reviewed. from these vehicles that were applicable to center trucks on During Phase 2 further literature was identified--some of partial low-floor cars. which was seen as being especially relevant, including the reports As in the case of the literature review, the review of design issued by TCRP Projects D-2 and D-7, which were now available. and performance data was prioritized to first consider infor- Only the MBTA and TriMet Portland appeared to have written mation with the highest potential utility. This was to maxi- up their experience in the United States and Canada and so expe- mize the effectiveness of the task within resource constraints rience elsewhere could not be determined by a literature search and in light of potential availability issues resulting from the when the research was undertaken. Some European systems had sensitive nature of some of the relevant information. reported on their experience in operating vehicles of this type. All seven transit agencies that operate this type of car were Berlin and Duisburg had reported on experience with 100- asked in the questionnaire for some specific information about percent low-floor vehicles and Essen had reported on experience these vehicles, track standards, experience associated with the of a 70-percent low-floor vehicle with four trucks. These cities use of the center trucks, and any mitigation the agencies might had experienced issues different from those seen in the United have introduced for overcoming issues. Six of the seven agen- States and the vehicles were not of the generic type under inves- cies provided detailed responses, along with supporting infor- tigation. Despite this, their findings about the principles involved mation such as drawings and maintenance procedures. This helped to inform Task 3. Some of the lessons learned were information proved to be of great value to this project. The expected to be applicable to the U.S. and Canadian vehicle types responses covered all the systems that had the most experience being studied. Some publications covering appropriate areas of of operating this vehicle type and that had experienced per- theory were identified but, in an area where the key develop- formance issues with this vehicle type before 2005. ments are both novel and recent and where commercial secrecy Further information was collected during Phase 2 by direct remains, these were not significant except as a means of identi- inquiry and as part of Tasks 7.2, 7.3, 7.7., and 7.12. fying the key factors. The main exception to this was the work carried on for TCRP Research Project D-7 and reported in TCRP Task 3. Contributing Factors Report 71, Volume 5, which considered performance issues with IRWs.All the literature reviewed is listed in Appendix F, together The project scope identified the following potential per- with a short summary of the content and its value. formance issues: Although the literature review was useful and was performed as planned, the amount of published information directly rele- Derailments, vant to this research project was very small. Although a more Excessive wheel and rail wear, and exhaustive search might identify further material, the costs of Reduced ride quality. doing this would probably not justify the small benefit. The value, therefore, was in confirming that this research was the The issues being observed were thought to be concurrent first to examine these issues in this particular way and, therefore, manifestations of multiple failure phenomena and, therefore, could provide useful guidance for the transit industry. even more difficult to isolate and identify. Effort in Task 3 was concentrated on identifying those factors that appeared to adversely affect LFLRV dynamic performance. This identifi- Task 2. Transit Agency and cation was done by circulating ideas internally in a table; these Manufacturer's Experience ideas were then discussed and refined by experts based on Priority was given to understanding the issues that have their collective experience. This analysis was used both as the arisen in the United States and the operating environment basis of the questionnaire designed to obtain key feedback within which LFLRVs operate in this country. To this end, a from U.S. and Canadian transit agencies (Task 2) and, com- targeted questionnaire was produced for the transit agencies bined with these results, to formulate preliminary guidance. operating LFLRVs. This questionnaire was scheduled after The initial findings proved sufficiently robust so as to at least significant progress had been made with Task 3, so that per- indicate situations likely to cause issues that might easily be tinent questions could be asked. avoided, especially with new systems. Some design and performance data were obtained from The contributing factors were assessed iteratively in dis- other sources, including internal libraries and files and cussions between the groups of technical experts. The results

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54 provided the basis for investigations in Phase 2 that were then LFLRV performance in combinations appropriate to U.S. combined in order to produce Chapter 3 of this report. applications. This was seen as giving most value from the The initial assessment indicated that certain features of resources available. As part of this modeling activity it was LFLRV design are likely to have a greater effect on the per- seen to be necessary to obtain further data and background formance issue areas being investigated than would be the information so that the results were truly representative. case with a traditional high-floor LRV. Based on the question- The modeling activity involved creating vehicle and track naire returns, this appeared to have led to significant diver- models that would cover the main combinations of design gence in the performance of different U.S. LFLRV designs. features. This assessment was checked against what could be In Phase 2, the researchers proposed investigating these diver- seen happening in practice by visits to representative U.S. gences in order to establish the optimum combination of transit systems using LFLRVs. parameters to minimize issues. At this stage, the following features appeared critical: Task 6. The Interim Report Wheel profile, in relation to rail profile; Covering Tasks 1 through 5 Flange angle; The report was prepared and some comments were Flange height; received from the Panel. Interfleet presented the report for Truck and truck-to-body attachment detail design and tol- discussion at the TCRP Project Panel C-16 meeting. The erances; and panel requested further information on the proposed Phase 2 LRV articulation design, including stabilizing links and Research Plan. A supplement was produced in order to pro- dampers. vide this information and replacing section 5 of the Interim Report and the associated appendices 8.7 and 8.8. The sup- Because lubrication was seen as beneficial, it was proposed to plement included more detail about why ADAMS/Rail was study this as well in Phase 2. selected as the modeling tool. Some of the more serious issues were clearly associated with track geometry. Four issues were apparent from Phase 1 work: Wheel and rail profiles must be compatible. Task 7. Execution of the Sharp curves (under 25 m/80 ft radius) should be avoided. Approved Research Plan Where they exist, special measures such as low speed restric- Phase 2 concentrated on modeling the features identified tions, track lubrication, and restraining rail may be necessary. as critical for LFLRV performance in combinations appro- Switches and crossings need to provide as smooth as pos- priate to U.S. applications. Vehicle and track models were sible transit for LFLRV wheels and wheels need to be ade- created to cover the main combinations of design features quately checked by restraining rail. found on the generic LFLRV type under consideration. This The maintenance standards need to keep the track param- activity formed the core of Task 7, which was divided into eters within the tighter tolerances that may be necessary for 14 subtasks. LFLRVs. ADAMS/Rail was used to undertake detailed analysis of track and vehicle conditions. Rail vehicle models were created by entering the required assembly data into forms. Task 4. Working Paper ADAMS/Rail then used the data to automatically construct A working paper was prepared to bring together the prin- the subsystem models and full-system assemblies building a cipal data collected during the performance of Tasks 1 complete, parametric model of each light rail vehicle being through 3 that was likely to influence subsequent work. It was studied. used to develop the Phase 1 report, including discussions on Tracks were also modeled in ADAMS/Rail, defining the the research needed in Phase 2 (Task 5 of Phase 1). track centerline by specifying the analytic layout parameters: curvature, cant, and gauge. Track-measured data was speci- fied as irregularity parameters: alignment, cross level, and Task 5. Identification and Planning gauge variation. The virtual vehicles were run through a series of the Research Needed of kinematic, static, and dynamic tests to determine the vehi- in Phase 2 cle's stability and derailment safety. The conclusions of Phase 1 were that Phase 2 should con- Information was requested and obtained from two other centrate on modeling the features identified as critical for major U.S. and Canadian transit systems to determine why

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55 they had not introduced this type of vehicle onto their create representative models of them. These design modifica- systems. tions included Articulation roll stiffness, Task 7.1 Identification of the Parameters Pitch damping of articulation, Required for the Vehicle Models Different solutions for stabilizing the pitching mode of the Models were created of the following vehicle types: body section above the center truck, Variation in the lateral secondary suspension stiffness, and A high-floor LRV closely based on the MBTA Type 7 car. Different wheel and rail profiles. An LFLRV closely based on the MBTA Type 8 car, and An LFLRV closely based on the Kinki Sharyo New Jersey, These variations, which were easily implemented in the Newark Subway car. parameterized model, allowed study of the effect of design changes on the behavior of the vehicle. Although these are These represented a traditional high-floor articulated vehicle, a comparative rather than absolute analyses, they gave the basis low-floor vehicle that has experienced some issues, and a low- to fulfill the project objectives. floor vehicle that is reportedly successful. The design of all three vehicles conforms to the generic vehicle type outlined in the Task 7.4 Develop Vehicle Models Research Project Statement but the detail designs of the three Vehicle models were created for the vehicle types listed cars are known to differ substantially from one another. These above. This work included coordination of data collection in basic models were subjected to a range of detail variations dur- Tasks 7.2 and 7.3 so as to achieve compatible treatment of each ing the modeling work in order to increase the breadth of the one. Figures A-1 through A-3 are representations of the three results. These variations are discussed in Task 7.3. models. A list of all the information required to cover all the options to be modeled was prepared; this took into account the capa- bility and structure of the model being used. A technical memo was prepared with 3 parameter list documents and cir- CENTER TRUCK culated among the team. These parameter lists were eventu- ally completed following the visits to transit systems (Task 7.12); in the meantime estimated values were used. Task 7.2 Collect Data on U.S. Vehicles The lists created in Task 7.1 identified missing parameters that were required by using a color code. Red indicated infor- mation definitely required; yellow indicated where it was pos- sible to make assumptions or use available unconfirmed data without serious effect on the results. Sensitivity analyses were performed to quantify the possible errors of the output. Before the visit to transit systems (see Task 7.12) a memo was produced that identified the most important questions to The MBTA Type 7 vehicle produced by Kinki Sharyo is a standard vehicle be answered. During the visit some new insights were gained (not low-floor) with normal trucks and wheelsets. The main vehicle parameters and more accurate parameter values were obtained, mainly are: for the MBTA Type 7 cars. Overall length 21.95 m Overall mass 35,500 kg empty, 48,670 kg full Axle load 9.3 t motor truck, 7.7 t trailer truck (max. load, from model) Task 7.3 Collect Data on Alternative Pivot distance 7m Vehicle Designs Wheel base 1.905 m Number of sections 2 Motor trucks (2) 2 standard wheelsets The key parameters of the models were varied in order to Trailer truck (1) 2 standard wheelsets, arranged between the car bodies, gage the effects of introducing different design features. The selfsteering, independent of car bodies Inter-car connection Common crown bearings, no dampers purpose of this task was to gather information on alternative components or arrangements that exist in order to be able to Figure A-1. MBTA Type 7.

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56 loop of analyses described under Sub-tasks 7.10 and 7.11 (ini- tial assessment). The others were performed following the visits to transit systems, which permitted the models to be refined. Task 7.6 Create the Equivalent Model Modifications The model and parameter options described in Sub-task 7.5 were implemented in the ADAMS/Rail template based vehicle models. Modifications concerning the structure of the vehicle (adding or removing elements) resulted in a new ver- sion of the model whereas parameter variations were covered by different sets of parameter files. For every option, an ADAMS solver input file was generated and the collection of The MBTA Type 8 produced by Breda has a low-floor area in the central part input files was run as a batch queue. including the center section (C-car) which is therefore equipped with independently rotating wheels. The pitching stability of the center section is achieved by anti-pitch spring elements. This vehicle type has experienced derailment problems and high wheel wear on the center section (C-car). The main vehicle parameters are: Overall length 21.95 m Overall mass 38,460 kg empty, 47,360 kg full Axle load 9.3 t motor truck, 6.8 t trailer truck (max. load, from model) Pivot distance 7.14 m Wheel base 1.905 m Number of sections 2 end sections, 1 short central section rigidly connected (in yaw) to the central truck Motor trucks (2) 2 standard wheelsets Trailer truck (1) 4 single wheels on 2 rigid cranked axles, pitching stabilized by a spring system Inter-car connection 2 spherical bearings at either end of the central truck, no dampers, roll inhibited by lateral bars at roof level Figure A-2. MBTA Type 8. Task 7.5 Creation of the Vehicle/Track Options Matrix The purpose of this sub-task was to define combinations The Kinki NJT LFLRV has a low-floor area in the central part of the vehicle of vehicle features and track layouts that gave a wide range including the center section (C-car) which is therefore equipped with independent rotating wheels. The pitching stability of the center section is of possibilities in order to identify those parameters that are achieved by a system of bars (Z-link) arranged on the roof of the vehicle. This crucial in terms of derailment prevention. Table A-1 shows vehicle is reported to perform satisfactorily. The main vehicle parameters are: which basic runs were undertaken using the existing vehicle Overall length 26.7 m. Overall mass 45,790 kg empty, 59,440 kg full. designs: Axle load 10.2 t motor truck, 9.4 t trailer truck (max. load, from Both empty and fully laden vehicles were modeled; this is model). Pivot distance 10.15 m. because although from the point of view of safety against Wheel base 1.9 m on motor truck, 1.8 m on trailer truck. derailment the empty vehicle is most critical, it is possible that Number of sections 2 end sections, 1 short central section rigidly other factors (like wheel/rail forces) might get critical at full connected (in yaw) to the central truck. Motor trucks (2) 2 standard wheelsets. load. Trailer truck (1) 4 single wheels on 2 rigid cranked axles. Parameter variations were defined based on the assessment Inter-car connection 2 crown bearings with pitch hinge on either side of the central truck, a pair of dampers between central and of possible alternative design options used in other vehicles end section, pitch stabilization of the central section by (see Sub-task 7.3) and in order to cover uncertainties in the a system of bars at roof level (Z-link) connecting all three sections. model inputs. Table A-2 provides an overview of all the analy- sis cases considered. Cases S1 to S3 were performed in the first Figure A-3. NJT.

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57 Table A-1. The basic modeling runs. No. Vehicle/Condition Track 1 KS New Jersey TCRP D-7 New Jersey MBTA "worst High speed High speed LFLRV - empty reference new case" track track (worn) 2 KS New Jersey TCRP D-7 New Jersey MBTA "worst High speed High speed LFLRV - full (fully reference new case" track track (worn) laden) 3 MBTA No. 7 - empty TCRP D-7 New Jersey MBTA "worst High speed High speed reference new case" track track (worn) 4 MBTA No. 7 - full TCRP D-7 New Jersey MBTA "worst High speed High speed (fully laden) reference new case" track track (worn) 5 MBTA No. 8 - empty TCRP D-7 New Jersey MBTA "worst High speed High speed reference new case" track track (worn) 6 MBTA No. 8 - full TCRP D-7 New Jersey MBTA "worst High speed High speed (fully laden) reference new case" track track (worn) Notes: "TCRP D-7 reference" means the track parameters identified in TCRP Report 71, Volume 5 (Wu, Shu, Wilson), in the work on the investigation of wheel flange climb criteria for transit vehicles. "New Jersey new" refers to a track of the Hudson-Bergen line as defined in the track design manual. "MBTA "worst case"" refers to track parameters assuming extreme MBTA track geometry and track at the limits accepted in current MBTA maintenance standards. MBTA track was chosen because this is a long-established system in contrast with a typical new build. "High speed track" means a synthetic track definition defined specifically to study derailment at high speed on (nearly) straight track sections. "High speed track worn" is a variation with significant rail wear following the information obtained during the visit to transit systems. Task 7.7 Collect specific U.S. Track Data carried out. This showed that the German Standards and guidance (BOStrab/VDV) were not prescriptive in general Tables were produced to compare the track standards used terms but deal with a process that trained engineers need to on seven of the eight transit systems LFLRVs identified in apply to their systems, based on their own knowledge of them Phase 1. Data for another modern light rail system was also and of standards that have been adopted in the past. One rea- included, because comprehensive information was in hand. son for this is that most systems in Central Europe have The tables also showed equivalent U.S. national standards and existed for a long while and parameters vary as a conse- the equivalent German standards. Notes were made of where quence. It was, therefore, decided that it would be useful to practice varies from the U.S. standards, e.g. where tighter tol- give the MBTA track standards to engineers in the research erances are being applied. A table was produced for each of team who had experience of accepting LFLRVs on a repre- the following issues: sentative German system to determine if they would make changes based on BOStrab/VDV practice. This exercise high- Wheel and rail profiles, lighted some specific differences that may be having an effect: Sharp curves, Switch and crossing transitions, Smaller ballast not taking up forces as well, Track standard tolerances, Gauge variation, Gauge tolerance on tangent track, Check rail clearances, and Tangent track between curves, Permitted number of defective ties. Parallelism of rails, Flangeway clearance on special trackwork, and The detailed comparison is included in this report as Track twist. Appendix E. The purpose was not to create comprehensive tables of data Task 7.8 Track Model Features but more to identify where any notable discrepancies likely to have an effect on LFLRV operation might exist and allow rec- Decisions were made on what track conditions would be ommendations to be made where necessary. representative to model and what specific features should be As part of this work a detailed comparison of typical U.S. included. Table A-3 shows the parameters of the first three practices with the equivalent German standard was also track options.

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58 Table A-2. Analysis cases. No. Vehicle / Condition Track(s) S1 KS New Jersey LFLRV MBTA "worst case" Reduced roll stiffness (1/10) of the inter-car articulations New Jersey new TCRP D-7 reference S2 KS New Jersey LFLRV MBTA "worst case" Z-link (inter-car stabilizing mechanism) removed S3 MBTA No. 8 MBTA "worst case" Increased roll stiffness (x10) of the inter-car articulations S11 KS New Jersey LFLRV - empty High speed track Wheel profile with 63 flange angle High speed track worn MBTA "worst case" S12 KS New Jersey LFLRV empty TCRP D-7 reference Inter-car dampers removed MBTA "worst case" S13 KS New Jersey LFLRV - empty TCRP D-7 reference Inter-car dampers between all cars (2 sets of 2) MBTA "worst case" S14 KS New Jersey LFLRV empty TCRP D-7 reference Z-link replaced by a pitch stabilizer spring MBTA "worst case" S15 KS New Jersey LFLRV - empty High speed track Wheel profile with 63 flange angle plus inter-car dampers between all cars (2 sets of 2) S16 KS New Jersey LFLRV empty High speed track Wheel profile with 63 flange angle plus Z-link replaced by a pitch stabilizer spring S21 MBTA No. 8 - empty High speed track Wheel profile with 63 flange angle High speed track worn MBTA "worst case" S22 MBTA No. 8 - empty TCRP D-7 reference Inter-car damper analogue to KS New Jersey LFLRV MBTA "worst case" S23 MBTA No. 8 - empty High speed track Wheel profile with 63 flange angle plus inter-car damper analogue to KS New Jersey LFLRV S24 MBTA No. 8 - empty TCRP D-7 reference Two sets of inter-car dampers MBTA "worst case" S25 MBTA No. 8 - empty High speed track Wheel profile with 63 flange angle plus two sets of inter-car dampers S31 MBTA No. 7 - empty High speed track Wheel profile with 63 flange angle High speed track worn MBTA "worst case" Data extracted from the TCRP Report 71, Volume 5, reference parameters on this behavior, a pair of track layouts was (Exhibits 41-6) as model input. The curvature was transformed defined as follows: so as to consist of circular curve sections joined by spiral sec- tions. The original curvature data was assumed to correspond Curve radius 2000 m allowing high speed but imposing a to the formula: degree = 5729.578/R for R in feet. The superel- flange contact on one side evation was transformed so as to consist of constant sections Lateral track irregularity of amplitude 3/4 inch over a and linearly varying sections. Lateral and vertical track excita- length of 20 feet in order to see separately the effect for tions for both rails were set to zero at X = 30 m (98 ft). every truck Some of the reported derailment issues involving MBTA 115 RE rail profile (new rail) and a worn shape as type 8 cars occurred on straight track sections at high speed described by the transit system engineers during the US at a time when wheel profiles with a flange angle of 63 were visit. The wear shape and original rail profile are compared in use. In order to assess the influence of other system in Figure A-4.

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59 Table A-3. Track option parameters. Model NJT New Track TCRP Report 71, MBTA worst case Volume 5 Reference Track type Ballasted Ballasted Ballasted , Note A Rail profile 115RE 115RE 115RE, Note A Rail inclination 1:40 1:40 1:40 Track gauge 56.5in 56.5in 56.5in straight, 57.5in curve Where measured 5/8 in below rail head Curve radius 300ft See below 44ft Vertical curve See below 400ft (combined) Spiral length 130ft (2 of) See below 20ft (2 of) Circular length 180ft See below 46ft Superelevation 4in See below Note B Track irregularity See below Note C Design speed 23mph 38mph 4.5mph Note A. Although some of the worst conditions occur on embedded track the Figure A-5. Continuously varying curvature in sections. application of the same rail sections in all these cases allows the separation of rail profile issues from other track quality issues. Note B. Negative elevation 1.25 in (32 mm), starting at 36 m, fully established track model. The continuously varying curvature was trans- 40m to 50m, removed with end of curve spiral (based on MBTA limits for track maintenance). formed into a sequence of sections with constant curvature Note C. Track irregularity 1.25 in (32 mm) lateral on outer rail in inward direction, and transition spirals (named "Standardized" in Figure A-5) on a length of 31.5 feet (based on MBTA limits for track maintenance). and slightly modified to include a straight section around t=120 ("Standardized modified"). Task 7.9 Develop Track Models Task 7.10 Simulation Runs Three track models were created using the material from Sub-tasks 7.7 and 7.8 covering the basic options defined The basic simulation options given in Table A-2 and sen- under Sub-task 7.5. Details of the track features are given in sitivity cases S1 through S3 identified in Task 7.5 were run 7.8. After the visit to transit systems, a fourth track was added. using ADAMS/Rail. A selection of typical results is shown in This track contained a curve with large radius and a single lat- Tables A-4 through A-9. These results were obtained with eral inward track irregularity on the outer rail. It allowed preliminary model and track parameters. Wheels are num- comparison of the vehicle models with respect to the derail- bered in the form wij, where i is the axle index and j=1 is for ment at high speed on straight tracks observed for the MBTA right and j=2 for left wheels respectively (Figure A-6). Forces Type 8 central truck. are shown in Newtons (N) (1 lbf = 4.45 N). Lateral forces are The track models are defined in ADAMS/Rail as a sequence negative if the wheel is pushed inward (this is usually the of straight and curved sections joined by spiral transitions. case for an outer wheel in a curve). The curves modeled are The software versions used in this project require a straight right curves; therefore the leading outer wheel of the center section between two curved sections of different radius. This truck is w32. is an acceptable restriction for most practical purposes but it required some adaptation for the TCRP Report D-7 reference Table A-4. Wheel-rail lateral force (N), NJT new track. Vehicle w32 w41 NJT_Full -23 kN 2.5 kN Type 7_Full -27 kN -2.5kN Type 8_Full -17 kN 1.5kN Table A-5. Wheel-rail lateral force (N), TCRP Report 71, Volume 5 track. Vehicle w32 w41 NJT_Full -23kN 3kN Figure A-4. Comparison of wear shape Type 7_Full -10kN 3kN and original rail profile. Type 8_Full -18kN 2kN

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60 Table A-6. Wheel-rail typical lateral force (N), MBTA worst-case track. Vehicle w12 w21 w32 w41 NJT_Full -42kN -19.5kN -32kN -27kN * Type 7_Full -37kN -19kN -34kN -20kN Type 8_Full -37kN -20kN -15kN -14kN *Unsteady peak value Table A-7. Maximum L/V, NJT new The highest peak lateral forces occur in the perturbed zone track. of the TCRP Report 71, Volume 5, track and again the max- imum was found for the NJT LFLRV. Vehicle w32 w41 The maximum L/V ratios are found in the perturbed zone NJT_Empty 0.43 0.05 of the TCRP Report 71, Volume 5, track and the vehicles Type 7_Empty 0.50 0.07 with single wheels (MBTA Type 8 and NJT) were most Type 8_Empty 0.45 0.02 affected. Table A-8. Maximum L/V, TCRP Report The MBTA Type 8 vehicle, which has reportedly encountered 71, Volume 5, track. various difficulties in service (e.g., derailment and excessive Vehicle w32 w41 wear), behaved quite satisfactorily in the simulation. NJT_Empty 0.93 0.22 The analysis results obtained for the sensitivity cases S1 to Type7_Empty 0.51 0.10 S3 showed only minor effects: Type 8_Empty 0.80 0.30 The modification of the roll stiffness of the articulations between the end sections and the central section with sin- Table A-9. Maximum L/V, MBTA worst- case track. gle wheels has no significant effect on the wheel unloading. This meant that the vehicle could be considered to be rigid Vehicle w32 w41 in torsion for all the cases considered. NJT_Empty 0.60 0.72 The removal of the Z-link did not affect wheel/rail forces. Type 7_Empty 0.62 0.50 However it did lead to a progressive pitch deformation, Type 8_Empty 0.47 0.42 which was however developing slowly caused by the high damping factor of the inter-car dampers. A means of pitch stabilization is required (Z-link or an alternative Task 7.11 Initial Assessment solution). The analysis results obtained with the preliminary vehicle models showed a similar behavior of the vehicles. Although some observations may have depended on preliminary data, the following general tendencies were observed: Task 7.12 Visits to Transit Systems Visits were made to discuss four transit systems with lead- The MBTA worst-case track had the smallest curve radius ing engineers involved in their operation and maintenance. and may therefore have produced the largest steady lateral Questions and agendas were prepared in advance. forces caused by a large angle of attack. The maximum The team was able to have other discussions to discuss forces were obtained for the NJT LFLRV. results, exchange and obtain information, and see and expe- rience the systems, vehicles, and maintenance facilities. Task 7.13 Simulation Runs The information gathered during the visit to the tran- sit systems allowed finalization of the vehicle models and completion of the model options as described in Sub- Figure A-6. Simulation run numbering. task 7.5. An overview of the simulation output is provided

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61 in Tables A-10 to A-22 and Figures A-7 through A-9. The Table A-11. Wheel-rail lateral force (N), main outcome can be summarized as follows: TCRP Report 71, Volume 5, track. Vehicle/Condition w32 w41 The overall behavior of the three vehicle types was found Type7/empty -4.5kN +8.2kN to be very similar. All the vehicles were able to negotiate Type8/empty -30.8kN -12.2kN small radius curves without excessive L/V ratios. NJT/empty -20.8kN -13.3kN The vehicles with single wheel trucks (NJT LFLRV and Type7/full -6.4kN -10.8kN MBTA Type 8) produce higher lateral forces in narrow Type 8/full -28kN -13.5kN curves as expected. This was expected to increase noise and NJT/full -32.8kN -20.1kN wheel-rail wear. NJT/empty S12 -47.2kN -37kN The pitch stabilization of the cars with a center truck was NJT/empty S13 -28.6kN -10kN solved in two different ways: The NJT vehicle had a link NJT/empty S14 -50.6kN -12.5kN mechanism (Z-link) connecting the three car bodies at the Type 8/empty S22 41.2kN 11.3kN roof level whereas the MBTA Type 8 had a torsion spring Type 8/empty S24 41.2kN 12.2kN system located in the truck. The Z-link introduced some asymmetry, which resulted in the vehicle running eccentri- cally close to one rail even on straight tracks. Similar effects Table A-12. Wheel-rail lateral force (N), would be produced by manufacturing tolerances with any MBTA worst-case track. vehicle design. The MBTA Type 8 solution is prone to Vehicle/Condition w32 w41 dynamic pitching modes caused by the damper design. Type 7/empty -27.3kN -12.3kN Inter-car dampers tended to reduce the pitching mode of Type 8/empty -10.8kN -10.5kN the center section. The MBTA Type 8 cars did not have NJT/empty -21.8kN -31.2kN dampers but by adding them into the model they were Type 7/full -44.7kN -18.35kN found to be especially beneficial. The disadvantage was a Type 8/full -17.6kN 12.9kN limited increase in the lateral forces and therefore the L/V NJT/full -37.5kN -38.4kN ratio. The best behavior was obtained with two pairs of NJT/empty S11 -28.5kN 30.1kN dampers (both articulations damped). However the NJT/empty S12 -32.6kN 31.7kN improvement was not significant. The modeling suggested NJT/empty S13 -34.8kN 32.3kN that only one pair of dampers was required for the NJT NJT/empty S14 -23.8kN 28.3kN LFLRV in order to limit the lateral wheel-rail forces. Type 8/empty S22 22.5kN 24.5kN The use of wheel profiles with low flange angles (63) Type 8/empty S24 21.5kN 20.8kN increased the tendency for derailment on all vehicles. There was a marked difference between the solutions with inde- pendent wheels and the standard wheelset truck of MBTA Table A-13. Wheel-rail lateral force (N), Type 7. The effect was accentuated when combined with high-speed track. worn rail profiles. Vehicle/Condition w32 w41 Type 7/empty S31 -14.9kN -8.6kN The MBTA Type 8 vehicle, which was reported to have derail- Type 8/empty S21 -21.1kN -16.8kN ment issues, had a very similar behavior to the NJT LFLRV. In NJT/empty S11 -27.1kN -10.6kN general, the lateral forces and L/V ratio were found to be even Type 8/empty S23 -20.6kN -6.8kN less critical. Type 8/empty S25 -19.6kN -6.8kN NJT/empty S15 -28.3kN -12.5kN Table A-10. Wheel-rail lateral force (N), NJT/empty S16 -25.3kN -12.5kN NJT new track. Vehicle/Condition w32 w41 Table A-14. Wheel-rail lateral force (N), Type 7/empty -20kN -2.6kN high-speed worn track. Type 8/empty -12.8kN -6.1kN NJT/empty -17.6kN 2.7kN Vehicle/Condition w32 w41 Type 7/full -30kN -6.45kN Type 7/empty S31 -11.1kN -3.8kN Type 8/full -14.3 kN -6.95kN Type 8/empty S21 -24.2kN -8.8kN NJT/full -19.8kN -3.68KN NJT/empty S11 -27.1kN -10.3kN

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62 Table A-15. L/V ratio, NJT new track. Table A-19. Wheel lift (mm), high-speed track. Vehicle/Condition w32 w41 Type 7/empty -0.56 -0.1 Vehicle/Condition w32 w41 Type 8/empty -0.44 -0.25 Type 7/empty S31 none none NJT/empty -0.49 -0.37 Type 8/empty S21 none none Type 7/full -0.56 -0.094 NJT/empty S11 none none Type 8/full -0.44 -0.22 NJT/empty S15 2 none NJT/full -0.44 -0.13 (short duration) NJT/empty S16 none none Type 8/empty S23 none none Type 8/empty S25 none none Table A-16. L/V ratio, TCRP D-7 track. Vehicle/Condition w32 w41 Type 7/empty -0.2 -0.15 Type 8/empty -0.72 -0.42 Table A-20. Wheel lift (mm), high-speed worn track. NJT/empty -0.61 -0.33 Type 7/full -0.2 -0.24 Vehicle/Condition w32 w41 Type 8/full -0.63 -0.39 Type 7/empty 1.4 none NJT/full -0.56 -0.41 (short duration) NJT/empty S12 -1.25 -0.95 Type 8/empty none 1.5 NJT/empty S13 -0.7 -0.21 (short duration) NJT/empty S14 -1.0 -0.3 NJT/empty none 1.5 (short duration) Type 8/empty S22 -1.32 -0.44 Type 8/empty S24 -1.32 -0.38 Table A-21. Angle of attack (degrees), Table A-17. L/V ratio, MBTA worst-case NJT new track. track. Vehicle/Condition w32 w41 Vehicle/Condition w32 w41 Type 7/empty 1.1 0.07 Type 7/empty -0.84 -0.48 Type 8/empty 1.0 0.15 Type 8/empty -0.49 -0.44 NJT/empty 1.1 0.2 NJT/empty -0.78 -0.87 Type 7/full 1.0 0.07 Type 7/full -0.75 -0.50 Type 8/full 1.0 0.15 Type 8/full -0.48 -0.44 NJT/full 1.0 0.1 NJT/full -0.68 -0.78 NJT/empty S11 -0.82 -0.83 NJT/empty S12 -1.0 -0.94 NJT/empty S13 -0.85 -0.94 Table A-22. Angle of attack (degrees), NJT/empty S14 -0.72 -0.75 MBTA worst-case track. Type 8/empty S22 -0.78 -0.85 Type 8/empty S24 -0.75 -0.78 Vehicle/Condition w32 w41 Type 7/empty 4.5 2.4 Type 8/empty 4.1 2.8 Table A-18. L/V ratio, high-speed track. NJT/empty 4.3 2.8 Type 7/full 4.6 2.3 Vehicle/Condition w32 w41 Type 8/full 4.1 2.8 Type 7/empty S31 -0.47 -0.13 NJT/full 4.3 2.6 Type 8/empty S21 -0.67 -0.28 NJT/empty S12 3.8 2.9 NJT/empty S11 -0.74 -0.36 NJT/empty S13 4.3 2.5 NJT/empty S15 -0.76 -0.42 NJT/empty S14 4.6 2.2 NJT/empty S16 -0.74 -0.40 Type 8/empty S21 4.2 2.7 Type 8/empty S23 -0.67 -0.28 Type 8/empty S22 4.2 2.7 Type 8/empty S25 -0.63 -0.28 Type 8/empty S24 4.2 2.7

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63 Figure A-7. Simulation Output 1. Figure A-8. Simulation Output 2. Figure A-9. Simulation Output 3.

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64 Task 7.14 Final Assessment of Results from the modeling and theoretical studies were being cor- rectly interpreted, based on their own experience of theoret- The results of the modeling, other investigations carried ical work. The other was to feed in any European experience out and conclusions of the visits to transit systems were of solutions that were being recommended where there is assessed as a whole in order to produce the input required for limited experience of applying them in the United States and Tasks 9 and 10. Chapter 3 of this report incorporates the Canada. results. The guidance, which forms Chapter 3 of this report, was The assessment process was based on the results of the prepared in draft and discussed by the team as a whole. modeling and other research and the experience and knowl- Having completed Tasks 7, 8, and 9, all the input required edge of individual team members. The discussion material in in order to make clear overall recommendations was now Chapter 3 is therefore an original collation of some of the lat- available. est thinking in this topic area by the experts involved. Drafts of the working paper (Task 8) were circulated and revised and each of the main contributory factors were discussed in depth Task 10. Develop Recommendations at the workshop held in Cologne (Task 9). for Further Research The research work was used as a basis for creating an ini- Task 8. Working Paper tial list that was then brainstormed at the Cologne workshop Summarizing the Results and further discussed by the team. Some issues were identi- of Task 7 fied. These tend to be of two types: This was issued for distribution to the panel for comment. Issues that could not be fully explored within the limits of the current budget and Areas of research in associated areas that are outside of the Task 9. Development of the scope but might provide alternative solutions. Guidance Required to Mitigate Performance Issues Task 11. Develop the Final Report A structured workshop took place in Cologne, Germany, at which the European experts in the team addressed both the The preliminary draft final report was issued with three issues associated with Task 9 and with Task 10. They concen- months allowed for the Panel to review it and for Interfleet to trated on two main issues. One was checking that the results provide the final text.