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50 CHAPTER 6 Conclusions The principal objective of this research was to provide introduce them and will mean that appropriate mainte- guidance on this topic. Complete understanding of all the nance standards must be applied. issues associated with the dynamics and performance of cen- 5. The introduction of LFLRVs to the United States and ter trucks on this type of LFLRV would be a considerable task; Canada has not had the same effect as in other parts of the therefore, these conclusions should be seen as observations world where this concept now dominates. Only two low- that have arisen during the course of this research. floor vehicle concepts have been applied, whereas other concepts might give better overall performance if they 1. Performance issues have arisen during the introduction of could be introduced. LFLRVs in the United States; however, in all cases they are 6. There does not seem to be any significant difference in the now being managed reasonably effectively and, as a result, standards used in the United States and those used in Ger- performance has improved. The solutions adopted may many that is affecting LFLRV performance. The compari- not be the optimum ones and are certainly not optimum son with Germany is appropriate because that country has for application in all cases. The issues that have arisen do a history of continuous large-scale streetcar and light rail not appear to be significantly worse than those that have development and a substantial body of accepted stan- arisen in other parts of the world during the introduction dards. There are, however, different philosophies in how of this type of vehicle. standards are applied. 2. The issues associated with introducing these cars to older 7. Each system in the United States and Canada has tended systems, where the track conditions may not be ideal, and to adopt its own specifications and solutions to emerging new ones where the infrastructure can be built to accom- problems. For example, nearly every system has its own modate them differ markedly. There are also issues associ- wheel profile. This lack of standardization makes intro- ated with introducing new vehicle types into an established ducing new technology and effective solutions to issues operating and maintenance culture, and compatibility much more difficult. with earlier, different car types. 8. The general advice to ensure that the wheel-rail interface 3. In terms of the vehicle, most performance issues are influ- is both compatible and managed properly is even more enced by the use of IRWs, rather than the configuration important for this type of vehicle. and attachment of the center truck. The issues are, there- 9. New systems that intend on using LFLRV should avoid fore, mainly those associated with the use of that type of the extreme track geometry that characterized older wheel and with the design of the wheel profile. streetcar lines and adopt standards appropriate to 4. Track standards must be appropriate for this type of vehi- the type of system for which these cars were originally cle. This may mean modifications to existing systems that developed.