US Standard Light Rail Vehicle

The US Standard Light Rail Vehicle (SLRV) was a light rail vehicle (LRV) built by Boeing Vertol in the 1970s. The Urban Mass Transportation Administration (UMTA) of the United States Department of Transportation (USDOT) promoted it as a standardized vehicle for U.S. cities. Part of a series of defense conversion projects in the waning days of the Vietnam War, the SLRV was seen as both a replacement for older PCC streetcars in many cities and as a catalyst for cities to construct new light rail systems. The US SLRV was marketed as and is popularly known as the Boeing LRV or SLRV, and should not be confused with their prior lunar roving vehicles for NASA.

The SLRV was purchased by the public transportation operators of Boston and San Francisco; in service by 1976, the US SLRV proved to be unreliable and scrapping started as early as 1987, but the SLRV were not completely replaced in both systems until 2007. Although the SLRV itself was not successful due to poor reliability, it did set the general size and configuration for succeeding LRVs in the United States.

History

Origin

The original concept of the SLRV came to fruition in the late 1960s as the limited number of cities with PCCs in North America were looking for modern replacements for their aging rolling stock; the last PCC had been manufactured in 1952. In 1968, the MBTA in Boston, one operator of PCC streetcars, created a mockup for one end of a proposed "Type 6" streetcar out of wood; the Type 6 program was discontinued after MBTA decided the cost to produce it was too high. Meanwhile, Muni in San Francisco, released a request for proposals in 1971 to purchase 78 new cars, designed by the rail transit engineering firm Louis T. Klauder and Associates (LTK), to replace their aging PCC fleet. The new cars, which Muni called subway-streetcars, were touted as "specially designed for San Francisco, adaptable to both subway and surface conditions and seating more passengers than the present CCstreetcars." Muni received two bids in November 1971, with a low bid price of per car from Boeing. Both bids were rejected as being excessively costly because potential builders were forced to recoup development costs over a relatively small number of vehicles.

Düwag had built a prototype as a demonstrator for the Hanover Stadtbahn in 1970 (Hanover car 601 DE">:de:TW_601.html" ;"title="/nowiki>:de:TW 601">DE; in June 1971 MBTA ordered two more prototype "Hanover" cars, to be partially paid using a grant from UMTA. However, under Nixon shock">the Nixon administration's "New Economic Policy" introduced that fall, UMTA was not allowed to fund the grant. That policy, codified as "Buy America" in Title IV of the Surface Transportation Assistance Act of 1978, stated that UMTA could not fund any grants exceeding $500,000 for transit vehicles that were produced outside the United States unless an exception was approved by the Secretary of Transportation. Instead, Boston (MBTA) was directed to join with San Francisco (Muni) and Philadelphia (SEPTA) to design a new streetcar that could meet the needs of all three cities.

In response to the failure to procure the Type 6, Duewag, and LTK/Muni streetcars, UMTA organized the BSF (Boston and San Francisco) Committee to design a standardized light rail car to reduce per-unit costs, using the same concept under which the earlier PCC streetcars were designed. The Standard Light Rail Vehicle (SLRV) specification was developed by UMTA based on the 1971 LTK design for Muni in conjunction with potential operators (who were all currently operating PCCs) in Boston, San Francisco, Philadelphia (SEPTA), Cleveland (Shaker Heights), Pittsburgh (Port Authority), New Jersey, El Paso (City Lines), and Toronto (TTC) as well as industry consultants at Parsons Brinckerhoff and Louis T. Klauder and Associates. At the same time, a flood of defense conversion projects came to fruition as the result of government encouragement to help keep defense suppliers busy as the Vietnam War was coming to an end.

Contracts awarded

UMTA awarded a grant for to MBTA on October 20, 1972, towards the purchase of 150 SLRVs. On April 23, 1973, MBTA signed a contract with Boeing Vertol for the 150 SLRVs. On May 1, 1973, UMTA awarded Boeing-Vertol of Philadelphia, Pennsylvania the contract to produce the SLRV at a cost of approximately $300,000 per car, each for the Muni configuration and each for the MBTA configuration. Muni initially ordered 80 cars and the MBTA ordered 150, and production commenced the same day the contract was awarded at a combined cost of . MBTA was scheduled to receive its first SLRV for testing in February 1975, and the majority of its cars in 1976. The MBTA portion of the contract cost for 150 cars; later, the orders were expanded to 100 and 175 respectively, and the extra 25 cars for MBTA added another , of which UMTA awarded MBTA on June 10, 1974. The SLRV was the first American-built trolley since 1952.

In late 1974, the first new SLRV was operated on a short test track at the Boeing plant. The first demonstrator model was produced in 1975 and was intended to be an early Muni car, and ran tests in Boston for 11 weeks. Three cars (two in the Muni configuration, and one in the MBTA configuration) were shipped to the Transportation Test Center in Pueblo, Colorado in fall 1975 under a contract awarded to Boeing Vertol for engineering testing. MBTA received its first car for testing in September 1976, two years behind schedule. This first car was delivered with trolley poles in addition to the pantograph, as the MBTA was still in the process of reconfiguring its overhead lines to accommodate the latter.

Operators

The first four SLRVs (3415, 3416, 3418, and 3421) entered revenue service on December 30, 1976, on the MBTA's Green Line D branch. However, revenue service with the SLRVs was suspended on April 16, 1977 due to numerous derailments, with 31 SLRVs delivered at that point. In San Francisco, the first two SLRVs were delivered in October 1977, and as with Boston's first car, these cars featured trolley poles as conversion to pantograph collection was not yet complete. Production models were delivered starting in December 1978, these cars having only pantographs, at which time the two pilot cars were returned to Boeing, and later re-delivered without the poles. The first regular runs on the Muni system came on April 23, 1979, on a temporary shuttle service, with more extensive use beginning with the opening of the Muni Metro on February 18, 1980.

Because the layout of Muni had several branch lines converging into the Twin Peaks Tunnel at West Portal and more lines merging near Church, Muni SLRVs were intended to couple in up to a 4-car consist as they entered the tunnel and underground portions of the route; as they exited, they would uncouple to continue on their assigned lines. However, due to slow door cycling and a 3-second delay between the operator signal and actual brake release, the Muni SLRVs proved to be slower than the PCCs in surface operation, and Muni was unable to meet the planned 4-minute headways on individual lines that would allow 2-minute headways with coupled trains underground. In addition, trains could not be turned around to meet 2-minute headways at the terminal Embarcadero Station. A new Muni Metro Rail Center (later renamed the Curtis E. Green Light Rail Center) was constructed for storage and maintenance near the Balboa Park station after Muni decided to purchase the cars the MBTA had rejected.

The Greater Cleveland Regional Transit Authority tested MBTA car #3401 on former interurban lines in mid-1976, but ultimately declined to purchase the US SLRV, instead buying custom LRVs of a different design from Breda Costruzioni Ferroviarie. When Cleveland released a request for quote in September 1977, Boeing Vertol bid per SLRV, exceeding Breda's winning bid of per car.  Search for Accession Number PB295070 Ironically, Breda would later construct light rail cars that would replace the SLRV's in both San Francisco and Boston (see '' Replacements and retirement'' section). SEPTA of Philadelphia, Pennsylvania was initially interested (especially because the SLRV would be locally produced), but purchased custom LRVs from Kawasaki because the US SLRV would not clear the City Hall loop. SEPTA tailored the bid by specifying the vehicle width to be narrower than the SLRV specification to exclude it from consideration. The Kawasaki cars for SEPTA were assembled at the Boeing Vertol plant to meet "Buy America" requirements.

Although they already had traditional streetcars, Pittsburgh, New Orleans, and Newark would not purchase these. Pittsburgh would, like San Francisco, convert the legacy streetcar into light rail, using the (at the time) custom Siemens SD-400. New Orleans has to the present not introduced new vehicles (having also never used PCCs). Newark would hold out on PCCs until the 2000s, being replaced by Kinki Sharyo vehicles. No newly built light rail systems would use it either, with the first (San Diego) using the Siemens–Duewag U2 and most other systems using Siemens and/or Kinki Sharyo equipment at one point or another.

The US SLRV design also influenced the early design of the Canadian Light Rail Vehicle.

Issues

Before they were delivered, Boeing claimed the US SLRV would be reliable and virtually maintenance-free. From their earliest days of service, however, the SLRVs proved to be a major financial and mechanical nightmare. After the initial three months of service, the MBTA was forced to halt all light rail service on April 16, 1977 for nine or ten days due to equipment unavailability. The MBTA was unable to retire their PCCs; instead, MBTA instituted a PCC rebuilding program to augment the SLRV fleet and maintain Green Line service. In San Francisco, the problems with the SLRVs led to the Muni Metro not reaching its full potential until 1982.

According to the original design specification, the goals for mean time between failures were set at 1400 hours or for the propulsion and auxiliary electric systems, which assumes average operating speeds of ; 1500 hours or for door and step systems; and 4000 hours or for the friction brakes. In comparison, for 1982, Muni SLRVs were breaking down an average of every (40 hours at operating speeds); reliability rose to (120–133 hours) between failures by 1988, but this was still a failure rate almost 15× the frequency of the (1890 hours) MTBF for the Siemens–Duewag U2 used in the San Diego Trolley system.

In Boston, the MBTA was accepting new cars from Boeing-Vertol, but the cars were falling out of service faster than the MBTA's maintenance staff could repair them. In addition, the MBTA could not acquire replacement parts fast enough to repair the disabled SLRVs. In a desperate effort to keep as many SLRVs operating as possible, MBTA set aside 35 disabled cars to be cannibalized for replacement parts.

To help prevent the riding public from seeing the number of brand-new, but heavily cannibalized SLRVs, several of the cars were hidden around the system where the public was not likely to find them. A major newspaper story emerged when a reporter and a photographer managed to get into a section of the Green Line's subway which was not in use at the time and found it was full of cannibalized cars which had been abandoned in the tunnel. The MBTA had been towing the cars into the subway during the middle of the night when the subway was closed to the public. The story and photographs brought the problems with the SLRV into the public eye for the first time. After the story broke, out-of-service SLRVs began to appear in several storage yards which were easily viewed by the public, though this may have simply been due to the ever-increasing number of disabled cars.

MBTA purchased $2.2 million in spare parts in May 1978 to ameliorate further issues, and Muni purchased $1.5 million in parts, forewarned by the MBTA experience. Muni also requested to add 200 employees in order to maintain and run the new SLRVs. Shipments of US SLRVs to MBTA were suspended in June 1978 after 135 cars had been delivered due to ongoing issues, and MBTA prepared the 35 cannibalized cars for return to Boeing later that year. On October 9, 1978, MBTA rejected the final 40 SLRVs and directed Boeing-Vertol to retrieve the 35 cannibalized cars, concluding that poor fleet reliability meant that Boeing was in breach of warranty. By 1978, the first five cars had been delivered to Muni; those had already underwent three rounds of modifications based on the MBTA experience.

Settlement

On December 15, 1978, MBTA and Boeing signed an agreement that revised specifications to enable the full delivery of 175 SLRVs, but reliability issues continued through 1979. An independent commission recommended that MBTA reorganize its LRV program and take quick action to resolve those issues. The SLRV fleet availability typically was less than 50% of the total number of cars on the property for the first few years of service; during the second and third quarters of 1979, Green Line trains missed 12,201 weekday trips, a 184% increase over the 6,598 missed weekday trips over the same period in 1978. In May 1979, MBTA and Boeing signed an agreement to modify and refurbish the 35 cannibalized SLRVs, but MBTA maintenance workers threatened to strike after MBTA ordered Boeing to retrieve the SLRVs, demanding the work be conducted in MBTA shops; Boeing stated in July that it would not accept any more SLRVs from Boston (3 had already been returned) until the labor dispute had been resolved. MBTA, Muni, and Boeing began to meet during the summer of 1979 to determine who would be responsible for resolving the identified problems. Boeing made an offer in September 1979 which identified specific design issues that would be corrected at its expense, including leaking gearboxes, air conditioning compressor issues, and traction motor failures, but MBTA rejected the offer; around this time, MBTA hired product liability attorney and law professor William Schwartz to negotiate on its behalf in August 1979.

Boeing took the position that issues had been caused by poor maintenance, poor track conditions, driver errors, and cannibalization. Schwartz argued that availability of the SLRV was less than 90% and had cost MBTA between $75–100 million to that point. On November 19, 1979, MBTA and Boeing reached a settlement; in order to make up for financial losses due to equipment unavailability, Boeing-Vertol would return $40 million to MBTA for the cost of repairs and modifications to several cars. In addition, the MBTA was allowed to reject delivery of the 40 cars remaining from the amended 175-car order. At the time of the settlement, 41 of MBTA's 135 SLRVs were inoperable due to design issues, accidents, and/or cannibalization for parts, which would require an estimated to restore to operating condition. Under the terms of the settlement, all warranties were terminated, and any further repairs would be the responsibility of MBTA, not Boeing, although Boeing would deliver modification kits to MBTA, whose maintenance personnel would install them at MBTA's expense to correct the previously identified issues. Boeing would only warranty the kits for defects in the parts; if they did not resolve the issues, MBTA would be responsible for the cost of redesign as well. The size of Schwartz's fee for negotiating the settlement, , prompted an investigation by the Massachusetts legislature.

Final deliveries

The 40 rejected MBTA cars sat in storage at Boeing-Vertol's plant for a short time, until San Francisco's Muni purchased some of these cars at a steep discount. The first of the "Boston" cars which Muni purchased was to replace two SLRVs which had been damaged during preservice Muni Metro subway testing in 1979 and were deemed beyond economic repair. After the successful conversion of that first car, Muni ordered an additional 30 SLRVs from the rejected Boston units to further bolster their fleet. The "Boston" cars in San Francisco were modified to meet the needs of the Muni Metro, but were easily distinguished by the wood grain interior finish at the operator's cab and articulation section, which did not match the yellowish orange color (from the Walter Landor-designed "sunset" livery) on the cars delivered under the original Muni order of 100.

By 1980, Boeing was no longer marketing the SLRV.  In 1983 the last SLRVs at Boeing-Vertol's facility were delivered when the MBTA accepted nine remaining cars (#3535–3543) from the group of 40 that MBTA had previously rejected. MBTA also took delivery of five cannibalized "shells" in 1983; these had been delivered to MBTA in the 1970s, but were subsequently returned to Boeing in 1979. The title for these five cars reverted to Boeing because MBTA did not respond promptly under the terms of the 1979 settlement, and had been scrapped to supply parts in the meantime. The five "shells" were scrapped in 1988.

Design

The SLRV is a double-ended articulated light rail vehicle long overall (over the anticlimbers), in the same range as many heavy rail vehicles both at the time and now, but noticeably shorter than many other LRVs such as the at-minimum-81-foot Siemens S70 commonly found today, which rides on three two-axle trucks (six axles in total). The two end trucks are spaced from each end (couplers included) and from the center truck under the articulated section, allowing a minimum track radius of . The dimensions of the SLRV were determined by the existing track constraints of three proposed operators: MBTA (Boston), Muni (San Francisco), and SEPTA (Philadelphia). Each car has an "A" and "B" end separated by a central articulated section. Each side has three passenger doors wide: one near the operator's cab, and two straddling the articulated section; there is no door at the rear (trailing) cab (in the direction of travel). The tested empty weight of the vehicle (including of instrumentation) was ; for a normal load of 100 passengers, the vehicle was and for the crush load of 219 passengers, the vehicle was .

Each end truck carries a single DC motor which powers both axles and has a rated output of at 1135 RPM, operating on 285 VDC; the traction motor drives the wheels through a reduction gear set of 5.571:1. In the original 1971 LTK design for Muni, the center truck was also powered, giving a top speed of ; in the final SLRV specification, the center truck was not powered and the top speed was reduced to . Power to the traction motors is controlled through a solid state "chopper" circuit operating at a frequency ranging between 0 to 400 Hz for vehicle speeds up to , allowing a continuously variable control of power from the 600 V overhead lines rather than the traditional trolley control at the time, which used a varied number of discrete resistances to control motor current. Above , the power is not "chopped" and is instead applied directly to the traction motors.

Primary dynamic braking is accomplished by running the traction motors as generators and dissipating the electricity generated through two brake resistor grids; a friction brake consisting of a single inboard disc brake per axle is blended with the dynamic braking as needed. The friction brake alone is sufficient to hold a fully loaded SLRV (with 219 passengers) on a 9° slope. In addition, six electromagnetic track brakes are provided; on the Muni cars, the track brakes are controlled independently to hold the car in place when starting on a slope, and on the MBTA cars, the track brakes are blended into the main brakes. Dynamic braking was enabled by using a separate power source to energize the field coils on the traction motors; Boeing stated that regenerative braking was possible. Although regenerative braking was not implemented on the SLRV, it was enabled on the similar CLRV.

The articulated section allows up to 16° of rotation in the horizontal plane, 3° of vertical sag (center section lower than ends), and 4.3° of vertical crest (center section higher than ends), which permits the SLRV to traverse curves as sharp as inside radius, travel through valleys with a vertical curvature of , and crest hills with a vertical curvature of .

The SLRV rolls on lightweight Acousta Flex composite resilient wheels in diameter; these wheels use aluminum hubs separated from the steel rims/tires by a silicone rubber cushion. The cushion is thick and is injected in the threaded space between the rim and hub; the design was developed by Standard Steel and BART in the 1960s. The resilient wheels reduce squeal when negotiating tight curves. Interior noise was claimed to be 65 dB. The design of the trucks is adapted from the Japanese Shinkansen trains. The trucks are equipped with rubber chevron springs and pneumatic suspension, which automatically adjusts to maintain floor height with varying loads. Damping is accomplished by both hydraulic (lateral) and pneumatic (vertical) means.

The car body shells and truck frames were built by Tokyu Car Corporation in Yokohama and the motors provided by Garrett, with assembly at the Boeing plant in Ridley Park, Pennsylvania. After production was ended by Boeing, Tokyu Car Corporation built light rail cars for Buffalo Metro Rail which externally resemble the SLRV, but many differences, most noticeable the lack of articulation and the use of single-leaf pocket doors similar to the London Underground D Stock.

Differences

While Boston and San Francisco bought their cars at the same time and they appear identical externally, the cars have differences:

*Doors: The doors themselves, at first, were essentially the same. However, Muni's cars had moveable steps at the four center doors (those nearest the articulated section), which could be lowered for street-level boarding or raised for boarding from high-level platforms, such as those in the subway. The Boston cars did not have this feature and so must be boarded from street-level. The doors were designed to accommodate both types of stairs. These doors proved troublesome and the MBTA eventually replaced them with bi-folding doors, further distinguishing them from Muni's.
*Appliances: The MBTA SLRVs were fitted with air-conditioning units for Boston's humid climate. Due to San Francisco's relatively mild climate, the Muni SLRVs were provided with forced-air ventilation instead of air conditioning. The air conditioning units that the Boston cars were delivered with had problems such as sucking up dust and other debris from the subway tunnels and were later replaced with roof-mounted Sutrak air conditioners in the late-1980s to mid-1990s.
*Interior styling: The "Boston" cars featured wood grain interior finishes at the operator's cab and articulation section, while Muni cars had a yellowish-orange color interior. However, certain Muni SLRVs (numbered 1252 and 13xx) actually had the same wood grain interior finish as Boston's because those cars were originally built for Boston, who rejected and returned them to Boeing. Muni then bought these cars, had their air-conditioners removed and fitted them with all the features exclusive to its fleet. The wood grain in these cars is thus the only feature that distinguishes these cars from those originally made for Muni.
*Automation: Muni cars were equipped with cab signaling to enable automated operation through the Market Street Subway with planned headways as low as 60 seconds.
*The San Francisco cars originally had cushioned seats, but they were replaced with hard plastic seats in 1985, because of vandalism.
*Capacity: San Francisco's cars seated 68, while the Boston cars seated 52 until the MBTA later had four seats removed to better accommodate wheelchairs.

Problems

One of the largest issues was simply that the Boeing SLRV was a "compromise" car. Both Boston and San Francisco had very different needs for the SLRV: Boston needing a more traditional streetcar, while San Francisco needed a more specialized car for its Muni Metro subway. Because the San Francisco cars would use station platforms at both street level (surface stations) and high level (underground), the vehicle steps needed to switch between the two modes. This became a passenger flow problem since the Muni cars could only use the two center doors on the SLRVs in the subway: the front end of the car curved away from the high-level platforms too much to allow passengers to safely board or alight the cars. The narrow front end, in turn, was required by Boston so the SLRV could navigate the tight curves in the MBTA's 1897-vintage subway.

Professor Seymour Melman partially blamed the use of a longtime defense contractor. Boeing Vertol's customary client (US Department of Defense) was relatively budget insensitive, more tolerant of cost overruns, and had sufficient funding and workforce to conduct complex maintenance, all contrary to the needs and abilities of a municipal transit agency. The design team primarily had experience in aerospace design, not rail vehicles, did not make a serious effort to gain that experience, and did not design for ease of maintenance. In some cases, portions of the SLRV had to be disassembled by acetylene torch to access components.

Boeing marketed the SLRV as a system and took the role of an integrator, subcontracting the design and fabrication of major components to external suppliers from places as far as Germany, Japan, and the United Kingdom. This approach created uncertainty in component delivery dates and essentially precluded prototype testing in favor of meeting contracted schedule milestones, turning MBTA and Muni into, effectively, beta testers for the SLRV. Because no prototype testing was conducted prior to vehicle delivery, the appropriate identification and stock levels of spare parts could not be established before delivery, and MBTA was forced to cannibalize SLRVs for parts to maintain fleet availability during the early years of operation.

Other specific problems with the SLRV include but are not limited to:
*Derailments on tight curves, which would seriously damage the car's articulation section, itself problematic as Boeing designed its own articulated section so as to avoid obtaining a license from overseas builders such as Duewag.
*Another major problem was the shorting of electrical systems and premature failures in the car's motors and propulsion systems. Boeing used an advanced chopper control system for the cars as insisted by the federal government. While such systems have been implemented successfully in many subway, light rail and trolley bus systems, the systems installed in Boeing's cars were found to be overly-complicated for the transit systems' use.
*The SLRVs came equipped with overly complex plug doors, which were originally intended to accommodate high-platform operation for Muni in the Market Street Subway

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