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6 CHAPTER 2 LFLRV Technology and Applications 2.1 Conceptual Development Category 2--Vehicles with conventional motor trucks at each end but non-conventional center trailer trucks or TCRP Report 2 (2) described the development and appli- wheelsets; and cation of LFLRV technology in the United States and Canada; Category 3--Vehicles with innovative motored and trail- however, it was published in 1995 and much has happened in ing running gear throughout. the intervening 10 years. The first modern low-floor streetcar was introduced into service in Geneva, Switzerland, in 1984. TCRP Report 2 also introduced a classification system for Sixty percent of the floor level was at 480 mm (19 inches) trailer trucks: above rail. It was built by Duewag and ACM Vevey. Vehicles of this type are known as "partial low floor." Before this, the typ- T1 Four conventional wheels, two conventional axles; ical streetcar or LRV had an even floor height sufficient to T2 Four IRWs, two cranked axles; clear the wheels on all trucks. The partial low-floor concept T3 Four IRWs; was based on the fact that, if a significant proportion of the T4 Two small IRWs built into articulation; floor height was lowered, most users would benefit from eas- T5 Two conventional wheels, one conventional axle, ier access, including those most likely to need it. The partial steered by articulation; low-floor concept did mean, however, that steps or ramps had T6 Four small wheels, two conventional axles; to be included in the interior to provide access to the remain- T7 Two IRWs steered by the articulation; and ing high-floor areas. Steps and ramps might introduce safety T8 EEF wheelset. and space issues. Two innovations have facilitated the development of vari- Category 1 vehicles have low-floor areas between the ous low-floor concepts: independent rotating wheels (IRWs) trucks, so the trucks are not of the low-floor type. The pro- and Einzelrad-Einzelfahrwerk (EEF) wheelsets. IRWs are portion of low-floor area will be restricted by this approach. wheels that rotate on the stub axle or an equivalent bearing Since TCRP Report 2 was written, the Skoda Astra Streetcar medium; they may be steered as a pair by the vehicle articu- has been introduced in the United States; this is a three- lation or built into a truck in accord with normal practice. section articulated LRV with a low-floor center section. It is a EEF wheelsets have IRWs that are self steering. The yawing Category 1 vehicle because the center section has no wheels moment caused by the high angle of attack is used to steer the suspended from the end sections through the articulation and wheels, control being provided by a pivoting axlebar and a is, therefore, outside the scope of this study. low-level linkage, which ensures that the wheels remain par- Category 2 is of interest because it includes the low-floor allel. They are used as single wheelsets. Zurich cars with EEF vehicles with a center truck having IRWs that are the subject wheelsets also have car-bodycontrolled steering. of the current study. Table 2-1 provides data on the main types Partial low-floor vehicles have been achieved in several of vehicle produced in this category. Table 2-1 uses a notation ways. TCRP Report 2 used a categorization which can be use- to describe the wheel arrangement, which is described in the fully applied: Glossary (Appendix B). The vehicle designs marked with an asterisk were first introduced in the United States. Category 1--Vehicles with conventional motor and trailer The table shows how much various manufacturers have trucks throughout; been involved in these developments and the varieties of

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7 Table 2-1. Category 2 LFLRVs. Year Builder Model Number Center Wheel Sections Where used introduced built truck arrangement type 1984 Vevey Be4/6 39 T6 B' 2' B' 2 Geneva, St. Etienne 1987 GEC TSF 136 T2 B' 2' B' 3 Grenoble, Alsthom Paris, Rouen, St. Etienne 1989 Vevey Be4/8 34 T6 B' 2' 2' B' 3 Bern, Geneva 1990 Socimi T8000 33 T3 Bo' 2 Bo' 3 Rome 1990 Duewag NGT6C/ 283 T8 B'1'1'B' 3 Bochum, NGT6D/ Bonn, MGT6D/ Brandenburg, 6NGTWDE Dusseldorf, Erfurt, Halle, Heidelberg, Kassel, Muelheim, Oberhausen, Rostock 1993 Bombardier T 78 T5 Bo'1'1'Bo' 3 Vienna 1994 Duewag/ Valencia 31 T3 Bo' 2 Bo' 3 Lisbon, Siemens type Valencia 1994 Duewag 6MGT 64 T3 Bo 2 Bo 5 Ludwigshafen Mannheim 1994 Duewag 8MGT 5 T3 Bo 2 2 Bo 7 Ludwigshafen Mannheim 1994 DWA/ NGT8D 25 T6 Bo' 2' 2' Bo' 3 Magdeburg Alstom 1995 Duewag NGT8 56 T6 Bo' 2 '2' Bo' 3 Leipzig 1995 Adtranz/ GT6-70DN 45 T2 Bo' 2 Bo' 3 Karlsruhe Bombardier 1995 DWA Flexity 47 T2 Bo 2 Bo 5 Dresden Bautzen Classic NGT6DD 1995 Bombardier Flexity Swift 276 T2 Bo' 2 Bo' 3 Alphen, K4000 Cologne, Croydon, Istanbul, Minneapolis, Rotterdam, Stockholm *1996 Siemens/ SD- 79 T2 Bo' 2 Bo' 2 Portland Duewag 600A/660A 1996 ABB- Variotram 58 T3 Bo 2 Bo 5 Heidelberg, Henschel 6MGT-LDZ Ludwigshafen, Mannheim 1997 Tatra RT6N1 19 T3 Bo' 2' Bo' 3 Brno, Poznan, Prague 1997 Tatra KTNF6 36 T2/T3 B' 1' 1' B' 3 Brandenburg, Cottbus 1998 FIAT Cityway 28 T2/T3 Bo' 2 2 Bo' 5 Rome 1999 FIAT/Stanga T5000 54 T2/T3 Bo' 2 Bo' 3 Turin 1999 Alstom Citadis 401 68 T2 Bo' Bo 2 Bo' 5 Dublin, Montpellier 1999 Bombardier Flexity 40 T2 Bo' 2' 2'Bo' 3 Kassel Classic 8NGTW *1999 Breda Type 8 100 T2 Bo' 2 Bo' 2 Boston (continued on next page) product that have been developed, partly because of the have been T2, T3, T5, T6, and T8. The more recent develop- "modular" or "platform" approach that adapts a basic design ments have not used the T8 and the T5 option only appears to meet various specifications. The history of some of these once. developments is described in Section 2.2. Use of the T2 and T3 categories of independent wheel center The table also shows the extent to which the various cen- trucks is widespread and has been a sales success for various ter truck configurations have been applied. The types used manufacturers. This type is generally regarded as having lower

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8 Table 2-1. (Continued). Year Builder Model Number Center Wheel Sections Where used introduced built truck arrangement type *2000 Kinki 187 T2 Bo' 2 Bo' 2 Hudson- Sharyo Bergen, Newark, Santa Clara 2000 Ansaldo- T69 16 T3 B' 2' B' 3 Birmingham breda 2000 Alstom Citadis 301 69 T2 Bo' 2 Bo' 3 Dublin, Orleans, Valenciennes 2000 Bombardier Flexity 34 T2 Bo' 2' 2' Bo' 3 Essen Classic M8DNF 2002 Bombardier Flexity 40 T2 Bo' 2' Bo' 2 Dessau, Classic Halle NF2000 NGT6 2002 CAF 8 T2/T3 B' 2 B' 3 Bilbao 2003 Bombardier Flexity 26 T2 Bo' 2 'Bo' 3 Krakow Classic NGT6 2003 Bombardier Flexity 32 T2 Bo' Bo' 2' 2' 5 Dresden Classic Bo' Bo' NGTD12DD 2003 Bombardier Flexity 60 T2 Bo' 2' 2' Bo' 3 Frankfurt Classic NGT8'S' 2003 Bombardier Flexity 30 T2 Bo' 2' 2' Bo' 3 Schwerin Classic SN2001 2003 Alstom Citadis 500 28 T2 Bo' 2' 2' Bo' 3 Kassel 2003 Leipzig Leoliner 37 T2/T3 Bo' 2' Bo' 2 Leipzig Works *2003 Siemens Avanto S70 44 T2 Bo' 2 2 Bo' 5 Houston, Paris, San Diego 2005 Siemens NGT6D 45 T2/T3 Bo' 2 Bo' 3 Ghent 2006 Bombardier Flexity 50 T2 Bo' Bo' 2' 5 Dresden Classic Bo' NGTD8DD 2006 Alstom Citadis 500 50 T2 Bo' 2 Bo' 3 Den Haag technical risk than a 100-percent low-floor (Category 3) LRV but Section 1.3 demonstrated that 100-percent low-floor issues of high wheel wear on the center trucks are widespread. cars are now achieving a high level of successful applica- Some designs are more successful than others, and the tions in Europe and have taken a significant proportion of inherent sensitivity of the arrangement allows minor adjust- the market from the partial low-floor concept. One- ments to vehicle and truck design parameters to give signifi- hundred-percent low-floor cars offer the advantage of a cant benefits in running behavior. This has been borne out by uniform floor level as well as easier access, but often a uni- the research undertaken. form floor level can only be achieved with some restriction Vehicles with the T6 type of conventional, small-wheel on available floor space. There have been no applications truck have reportedly performed well. The small-wheel truck of this type, which falls in Category 3, to date in the United is always located fully underneath a body section and not States and Canada. mounted under a short "center section." The truck is free to The issue of adopting 100-percent low-floor cars was con- pivot and is not attached to the other body section. This may sidered in TCRP Report 2 (Chapter 3). The study concluded influence performance positively. that introduction into the United States and Canada on Single wheelsets designs (T5 and T8 categories) have not entirely new systems might prove difficult because been perpetuated beyond the early orders documented in TCRP Report 2. In particular the EEF wheelset-equipped cars New systems might not wish to assume the potential have reportedly not performed as well as anticipated in all liability for specifying lower buff loads, even though cases because of the high cost of maintaining the relatively no technical reason was identified why this cannot be complex steering system. done.