Click for next page ( 12


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 11
11 applications and how the products used differ from experi- Portland. The first section opened in 1986. There is also a ence generally. short streetcar line and a vintage trolley service. 2.3 Application in the United States LFLRV Fleet Table 2-6 summarizes the deliveries of the Category 2 The first batch of Portland cars were on order when TCRP LFLRVs in the United States with center trucks having IRWs. Report 2 was published. There were 46 cars and 6 more of this There are six basic car types, originating from three separate type (SD-600A) were added later. Portland also took delivery supply strands (i.e., [1]Siemens/Duewag; [2] Breda; and [3] of 27 cars of type SD-660A later, bringing the total fleet of Kinki Sharyo and Bombardier). Combining these car types LFLRVs to 79. TriMet has pointed out that the SD-600A and with the eight transit systems with differing characteristics SD-660A are virtually identical, so these are considered as one provides varied experience. type from here on. Appendix C provides more detailed information about most of these cars. Details of the Center Trucks Appendix D provides details of the systems over which these vehicles operate. The systems are grouped as old or new The center truck frames are rigid and have independent as follows: resilient 26-inch (660-mm) Bochum wheels on a cranked drop axle. The primary suspension is provided by conical Old--traditional streetcar systems opened before 1950, rubber chevron springs; the secondary suspension is pro- including those that have been modernized and extended vided by coil springs controlled by lateral and vertical but not reconstructed to modern LRT standards; and dampers. Resilient traction links control yaw. The center New--modern LRT systems opened since 1970. truck is braked. No vehicle-mounted lubrication is used. All seven transit agencies were surveyed for specific informa- Measures Undertaken When These Vehicles tion about these cars, track standards, experience with the use Were Introduced of the center trucks, and any mitigation they may have intro- duced for overcoming issues. A computer model simulation of the routes was used when The following sections describe the experience in each the vehicles were selected in order to check that the vehicles U.S. city, concentrating on those that have the most vehicles would be suitable. Vehicles were also test run on the routes or the most experience of performance issues. The informa- before being accepted. The supplier provided operation and tion is taken from a literature search, a questionnaire, visits maintenance manuals as well as training. to some of the systems, and correspondence as explained in Appendix A. Experience Using These Vehicles TriMet's experience in using these vehicles has generally 2.3.1 Portland TriMet been good. Wheel wear has been higher than for other types Infrastructure of car, but passengers have not raised issues about noise and ride comfort, and there have been no derailments. There The Tri-County Metropolitan Transportation District of would be no issue about introducing further cars of this type Oregon (TriMet) operates a 33-mile-long light rail system in or other types of LFLRV. TriMet is required to comply with the FTA Guidelines for Design of Rapid Transit Facilities in which interior noise Table 2-6. Category 2 LFLRV deliveries, should not exceed 78 dBA at 55 mph except in tunnels. TriMet North America. has exceeded these standards with wheels that are rough or City/system LFLRVs Years supplied with flat spots and on corrugated rail. Portland MAX Siemens/Duewag 1996-2004 SD-600A and SD660A Boston MBTA Breda Type 8 1999-2003 Measures To Reduce Issues NJ Transit Hudson-Bergen Kinki Sharyo 2000-4 and Newark Subway Wheel flange wear on the center truck occurs at a higher rate San Jose, Santa Clara VTA Kinki Sharyo 2001-4 Minneapolis Metro Transit Bombardier Flexity Swift 2003-4 than on the motor trucks as TriMet expected. The LFLRV cen- Houston METRO Siemens Avanto S70 2003-4 ter truck tends to produce more squeal than motor trucks. San Diego SDT Siemens Avanto S70 2004 About 20 wayside lubricators have been installed at sharp

OCR for page 11
12 curves in embedded track to mitigate wheel squeal from both low- and high-floor LRVs. These lubricators have been used for the past 2 years on girder rail, embedded track, and some open track; they also help reduce wheel and rail wear. They are con- sidered to have been effective. Lubricant is pumped through a 1/4-inch-diameter hole in the rail head at the wheel/rail con- tact area. On open track, TriMet also has about 10 wayside lubricators. Figure 2-1 illustrates a wayside lubricator. Residents have complained of noise from vehicles, and readings of 80 dBA have been made. This has been mitigated by rail grinding and keeping wheel profiles in good condition. 2.3.2 Massachusetts Bay Transportation Authority (MBTA) Infrastructure Figure 2-2. MBTA Type 8 LFLRV on the Green Line MBTA operates 31 miles of streetcar lines in Boston. These in Boston. lines developed out of a system that had its origins 150 years ago. The 25-mile-long Green Line, where LFLRVs are used, on a short test track, but trial running was also undertaken dates in part from 1897. Parts of this line are underground on the Green Line. The manufacturer provided specialized subway. Unlike the Portland Metropolitan Area Express operations and maintenance training and operations and (MAX) system, the Green Line is a long-established streetcar maintenance manuals. network with many potentially challenging infrastructure features. It is also one of the busiest systems of its kind in the Details of the Center Trucks United States and Canada, with relatively intense and com- plex services. The track used on the Green Line has relatively Figures 2-3 and 2-4 show views of the center truck used on severe geometry. Curves can be as tight as a 42-ft (12.8-m) the Type 8 cars. As explained in Section 2.2.3, this car design radius with no tangent track between reverse curves. is unique to Boston. The center truck frame is flexible. In plan view, it has two L-shaped elements with a spherical joint connection at the end of the shorter arm of each element (see LFLRV Fleet Figure 2-5). MBTA ordered 100 cars from Ansaldobreda, the first of The IRWs are mounted on a low-level cranked axle so that which was delivered in 1998 for testing (4). They were desig- they are constrained as if they were on a conventional solid nated Type 8 by MBTA and have been used only on the Green axle. The primary suspension consists of stiff rubber bushings Line. Figure 2-2 shows such a car. between the truck frame and the axle. These are formed of metal external and internal rings with rubber between them. Measures Undertaken When These Vehicles The rubber element is configured so as to give a variation Were Introduced The supplier ran a computer simulation of the Type 8 design, based on track conditions considered appropriate. Test running before operation in Boston was limited to 10 mph Figure 2-3. Center truck of MBTA Type 8 car (general Figure 2-1. Wayside lubricator. view).

OCR for page 11
13 Figure 2-6. Cranked axle arrangement, IRW and primary suspension (MBTA Type 8). Figure 2-4. Underside view of the center truck (MBTA Type 8). Experience Using These Vehicles between vertical and longitudinal stiffness. Figure 2-6 illus- trates this arrangement. Since the Type 8 cars were introduced in 1999, some derail- Four air springs are used to support the bolster; these are ments have occurred. MBTA has also experienced excessive arranged inboard of the axles, and each pair is linked from side wheel and rail wear associated with these cars. There have to side by a common leveling valve. The two ends are linked been issues with interior noise resulting from the difficulty of through a relay valve, which permits cross feeding. This damping the noise coming from the wheel-rail interface arrangement is controlled by two lateral dampers. Figure 2-7 within the tight space envelope. Ride comfort requirements illustrates this arrangement. As illustrated in Figure 2-8, the are met, although some yaw and pitching movements are center truck has an anti-pitching system using a torsion rod to noticeable. There have been no complaints from passengers provide stiffness. The roll control of the entire vehicle and of however. the center section is largely performed by transverse rods on the roof; the joints are spherical ball bearings in line with the Measures To Reduce Issues relative trailing axle. Figure 2-9 illustrates this arrangement. The vertical pitching of the center section is controlled by the In 2001, investigations began to study the causes of the air springs and anti-pitching bars; there is no pitch damping. derailments using simulations and a special test track facility. As a result a new wheel profile was introduced and track maintenance standards were altered (5). Derailments occurred on tangent track because of lateral disturbances caused by track irregularities. These irregulari- ties were a combination of gauge widening and cross level variation, which created a large angle of attack and caused wheel climbing. Vertical movement of the center truck causes a truck yaw rotation because of the arrangement of the trac- tion links. This is noticeable at speeds above 35 mph, and, at speeds above 40 mph, the lateral-to-vertical-force ratio is exceeded, increasing derailment risk. The manufacturer Figure 2-5. Articulated center truck frame (MBTA Type 8). Figure 2-7. Air spring control system (MBTA Type 8).

OCR for page 11
14 to remove the lip that had developed from wear. The mainte- nance interval was reduced from 6 to 3 months. Type 8 cars received the new wheel profiles first, followed by the earlier Type 7 high-floor cars. These earlier cars were not modified but are wearing to the new profile. At first wheels had to be re-profiled every 2,000 miles to keep them within limits, but now wheels can be used in excess of 30,000 miles before re-profiling is necessary. No derailments result- ing from dynamics have occurred since March 2003. Excessive wheel wear has been greatest on the motor trucks, with localized wear at the flange tip resulting in the flange angle degrading rapidly. At one time it was necessary to re-profile the wheels as often as every 2,000 miles, as men- tioned. This occurred because of changing the flange angle from the older Green Line standard of 63 to 75 degrees to mit- igate derailment issues. This was a transition issue and was overcome by seven measures: Very close monitoring of wheel profiles, Checking maintenance tolerances by use of dynamic modeling, Gauge face grinding of the rail, Design and grinding of a new railhead profile to promote better steering and reduced contact, Changing the profile on other cars in the fleet, Figure 2-8. Anti-pitching system (original design) Grouping cars with the new profile on one line, and (MBTA Type 8). Tests of a friction modifier. introduced a modification that allows the cars to operate up The early test results of the use of a stick lubricator on the to 50 mph without exceeding the limit at which the lateral-to- front and back flanges of the wheels on the motor trucks were vertical force ratio might cause derailment. inconclusive and were based on limited data. As mentioned, A modification has improved the control of yaw on the the overall result has been to increase the mileage between center truck. The modification consists of a virtual pivot with truing to more than 30,000 miles. traction rods. An asymmetric arrangement of two traction There has also been excessive rail wear from the same cause rods ties the bolster and truck frame together. Smaller "dog and re-grinding has reduced this issue. This has, however, bones" are tied to the truck frame to prevent rotation of the shortened the potential life of the running rail. The most severe wheelsets. The bolster-to-frame arrangement is being wear issues occur on tight-radius curves (less than 100-ft changed to a design that provides greater rotational freedom radius) and are caused by all vehicles. MBTA believes that IRWs between the truck and car body by introducing a virtual cen- actually may have lower contact forces on these sharp curves. ter pivot with limited rotational freedom. The addition of sound-deadening panels beneath the floor Part of the Green Line (the B Line) was changed to the new and inside the articulation bellows reduced the noise level track maintenance standard, and the railhead was re-profiled within the vehicles to limits that met the appropriate standards. 2.3.3 Newark Subway Infrastructure NJ TRANSIT operates the Newark Subway, which is a short (5-mile-long) remnant of a much larger streetcar network. Figure 2-9. Roof-mounted rods to prevent This route was built in a tunnel in 1935 and has survived as a inter-section roll (MBTA Type 8). relatively busy small transit system, with an extension now

OCR for page 11
15 under construction. The subway uses traditional streetcar technology, where the wheels have narrow tires, although it does not have any street running sections; it does have tight curves at the city center end of the route. LFLRV Fleet NJ TRANSIT introduced 18 Kinki Sharyo LFLRVs in 2000 for use on the Newark system (see Figure 2-10); this fleet is being expanded. Details of the Center Trucks Figure 2-11. Center truck (NJ TRANSIT Kinki Sharyo LFLRV). The center trucks were supplied by Fiat-SIG (see Figures 2-11 and 2-12). The center truck frames are rigid "H" type and have 26-inch (660-mm) Bochum IRWs on a low-level suitable. Vehicles were also test run on the subway and else- "cranked" beam referred to as an "idler axle." The primary where before being accepted. The supplier provided opera- suspension is provided by rubber chevron springs; the sec- tions and maintenance manuals and training. ondary suspension is provided by air springs. Resilient trac- tion links control yaw. The center truck is linked to the end Experience Using These Vehicles sections by bearings under the articulation and the relative movement is controlled by a pair of Z-links and two dampers NJ TRANSIT's experience in using these vehicles has gen- above one of the joints. These Z-links and dampers are roof erally been good although issues have occurred. mounted (see Figure 2-13). The center truck is braked and Wheel wear has been higher than for conventional cars. has track brakes. A REBS grease spray lubrication system has Center truck wheels wear faster than those on the drive axles. been tried on one car for over a year as an experiment. The Wheel turning started after 100,000 miles and was repeated at REBS grease spray lubrication system has two nozzles for each 30,000-mile intervals. This was causing the flange thickness axle end and sprays REBS friction modifier on the wheel. The to increase, so profile correction is necessary as part of the vehicles are fitted with a special wheel profile (see Figure 2-14), wheel turning. Although the subway is small, the depot is which is appropriate to the track geometry of the subway. equipped with a modern underfloor wheel lathe. NJ TRANSIT staff have observed that the truck's curving behavior on curved tracks and switches probably causes the excessive Measures Undertaken When These Vehicles wear. The hardness of the tires was designed to give optimum Were Introduced wheel and rail wear rates. A computer model simulation of the routes was used when Excessive rail wear generally occurs on curved track and the vehicles were selected in order to check that they would be typically on switches and crossings. The highest rate of wear occurs at the reversing loops in Penn Station. These reversing Figure 2-10. NJ TRANSIT Kinki Sharyo LFLRV in Figure 2-12. Lateral bump stops on the center truck Bloomfield workshop. (NJ TRANSIT Kinki Sharyo LFLRV).

OCR for page 11
16 Although passengers are not carried on this section, any excessive noise affects passengers waiting at the adjacent platforms. Ride comfort has not been an issue. There would be no issue about introducing further cars of this type or other types of LFLRV on the Newark Subway. Measures To Reduce Issues NJ TRANSIT has introduced house tops to stop derail- ments from occurring. House tops are fitted to all switches, except those operated infrequently. The noise issue on the Penn loop is being managed by using lubrication, gauge widening, flange way widening and installa- Figure 2-13. Roof-mounted Z-links and dampers tion of restraining rail at both rails (see Figures 2-15 and 2-16). (NJ TRANSIT Kinki Sharyo LFLRV). loops have radii of 60 and 82 feet. All cars pass around them, but they are not carrying passengers at the time. The inner rail on these curves is more affected. NJ TRAN- SIT predicts the need to replace the rails on these loops every 10 years but might be able to extend this to 15 by optimizing the performance of the wayside lubricators. Three derailments have occurred, but these have all hap- pened at slow speed on switches. The cause has been identified as the tendency of the center truck to curve. This side curving can cause derailment because of adjustment of the switch blade under the stock rail, thereby causing a step up and asso- ciated with a cross leveling of more than 1/8 in. toward the point of the switch. This has been identified as the cause in all cases. Noise levels are high on the Penn loop; figures of 109 dBA have been recorded when speed has exceeded 5 mph. Figure 2-15. Fully guarded switch in Penn Station. Figure 2-16. Rail surface friction conditioner at Penn Figure 2-14. Newark city subway wheel profile. Station, showing lubricant on rail surface.

OCR for page 11
17 route uses both girder (Ri59) and standard (115 RE) rail. The minimum curves are 30 m (98 feet) on the route and 25 m (82 feet) in the depot. LFLRV Fleet Kinki Sharyo has supplied a fleet of 100 LFLRVs to the Santa Clara VTA; these have an ALSTOM traction system (see Figure 2-18). Thirty were supplied in 2001-2 and a fur- ther 70 were supplied in 2004. Mileage is 30,000 to 120,000 miles per year per vehicle, with 42 required to provide the service. Figure 2-17. Friction conditioners for rail flange Details of the Center Trucks and guide rail in the workshop area. The center truck frames are rigid and have full inde- pendent resilient 26-inch (660-mm) Bochum wheels. The Gauge widening will increase the angle of attack, but in this sit- primary suspension is provided by rubber chevron springs, uation the derailment risk is low. the secondary suspension is provided by air. The center There are 12 lubricators in the yard to cover all turnouts truck cannot yaw because it is integral with the central and sharp curves (see Figure 2-17). Also there are four way- module. The center truck is braked. No vehicle-mounted side friction modifiers. Two are on the Penn loop and the lubrication is used. These cars are very similar to those in others are on a 100-ft-radius curve close to an apartment use by NJ TRANSIT (see Figures 2-19 and 2-20). building. Measures Undertaken When These Vehicles 2.3.4 Hudson-Bergen NJ TRANSIT Were Introduced NJ TRANSIT also introduced 29 LFLRVs of the same type Track is ground to provide uniform wear of the running as used on the Newark Subway onto the new Hudson-Bergen surface including asymmetric railheads on curves. line in 2000. A further order is pending. Vehicles were test run on the route before being accepted The Hudson-Bergen uses the AAR1B wheel profile (51/4 and the fact that NJ TRANSIT were already operating similar inches wide) and a different wheel back-to-back dimension vehicles was important. The supplier provided operation and (533/8 inches compared with 541/8 inches on the Newark Sub- maintenance manuals and training. way). No specific issues have been reported by NJ TRANSIT. Such issues as have been encountered with these cars on the Newark Subway are mainly associated with the more extreme geometry of older streetcar track. Hudson-Bergen is re-pro- filing all wheels at 30,000 miles, so wear may not have been identified as an issue. The maintenance of the cars is not car- ried out directly by NJ TRANSIT, but by the car builder under the Design, Build, Operate, and Maintain (DBOM) contract. 2.3.5 Santa Clara Valley Transit Authority (VTA) Infrastructure The Santa Clara VTA system of San Jose is a newly built light rail; it was inaugurated in 1987. The route is 30 miles long. The Figure 2-18. VTA Kinki Sharyo LFLRV.

OCR for page 11
18 Figure 2-21. Alteration to the VTA wheel profile. the truing interval and hence extend the life of wheels. Figure 2-21 illustrates this measure. Figure 2-19. Cranked axle under the articulation There have been issues with railhead corrugation on (VTA Kinki Sharyo LFLRV). embedded track since the system was opened and this has continued with the introduction of LFLRVs. Also anticipating issues, VTA installed wayside flange lubri- Experience Using These Vehicles cators in order to reduce wheel squeal on sharp curves. The VTA's experience in using these vehicles has generally been system is also experimenting with surface friction condition- good. There have been no wheel or track wear issues or derail- ers (see Figure 2-22). These measures are provided in order to ments and ride comfort has not been an issue. There would reduce wheel squeal for all types of car. be no issue about introducing further cars of this type or All vehicles are fitted with the supports and holders for other types of LFLRV to the system. flange, surface, and wheel back conditioning (see Figures 2-23 Noise is excessive on sharper curves (less than 600 feet through 2-25). All the sticks have, however, been removed radius), but this occurred with high-floor cars as well. because of concern about extending braking distances. The fleet has now accumulated more than 4 million miles Because of the high deceleration rate, the friction brake on and the VTA and its customers are very pleased with the per- the center trucks is heavily used. The brake discs are close to formance and ride comfort of these vehicles. No hunting, the wheel and the wheel bearings, causing the grease to warm noticeable resonance in the suspension, or other unpleasant up. The bearings have to be overhauled regularly because the side effect is attributable to the low-floor technology. Both properties of the grease change from this heat. interior and exterior noise emissions and vibration are within Center trucks are showing slightly more flange wear than specification. motor trucks and these trucks are noisier than motor trucks or older conventional cars. Measures To Reduce Issues Lubricators have been installed and these solve noise issues The wheel profile is being changed so as to provide an most of the time. extended transition between the conical part of the running Derailments have occurred, but these have all been surface and the flange. This is being done in order to reduce because of operator error and, in one case, an automobile collision. The moments transferred through the car bodies caused a high angle of attack of the wheels of the center truck (see Figure 2-26) Figure 2-20. Roof-mounted articulation dampers and Z-link. Figure 2-22. Surface friction conditioner, Santa Clara.

OCR for page 11
19 Figure 2-26. Side collision--the center truck derails because of the reaction of lateral loads. 2.3.6 Minneapolis Metro Transit Infrastructure The Minneapolis Metro Transit "Hiawatha Line," a new Figure 2-23. Holder for the wheel flange friction light rail system opened partly in June 2004 and fully in conditioner. December 2004, is 12 miles long (6). LFLRV Fleet The Hiawatha Line fleet consists of 24 Bombardier Flexity Swift type LFLRVs. These vehicles are based on the K4000 cars used in Cologne. Details of the Center Trucks The center trucks have IRWs. These trucks have radial arm suspension with the arms linked by a horizontal rod. The pri- mary springs are rubber and the secondary suspension is pro- vided by coil springs. Experience Using These Vehicles Figure 2-24. Holder for the wheel tread friction Operating experience is limited, although test running conditioner. began in March 2003. A low-speed derailment occurred in a maintenance yard in March 2005 (7). This was caused in part by excessive wheel wear, and the system instituted more reg- ular inspections as a result. The curve was said to be tighter than on the service route. Also, varying wheel wear had been found on the wheels of the center trucks on 22 of the LFLRVs, and they were still under warranty. 2.3.7 Houston MetroRail Infrastructure The MetroRail Red Line is a light rail system that began operation in Houston, Texas, in January 2004. It is 71/2 miles long and part of the Metropolitan Transit Authority of Har- ris County. Track geometry is not severe--the minimum curve being a 125-ft (38.1-m) radius. Most of the track is con- Figure 2-25. Holder for the wheel back face friction ventional 115 RE rail, although 80 percent of the route is conditioner. embedded.