User:Mliu92/sandbox/NABI CompoBus

The NABI CompoBus was a line of low-floor composite-bodied transit buses available in 40' and 45' rigid lengths manufactured by North American Bus Industries (NABI) between 2002 and 2013. In addition to the different available lengths, the buses were sold with a variety of prime movers, ranging from conventional diesel and LNG/CNG combustion engines to diesel-electric hybrid.

The CompoBus complemented the existing LFW line and the 40-foot models were essentially identical in appearance; the larger 45-foot Metro 45C carried distinctive styling. Because the bus body was assembled in Hungary using a licensed process, the CompoBus initially required a waiver from the FTA to exempt it from Buy America requirements. After New Flyer acquired NABI in 2013, all NABI product lines were discontinued in 2015, once existing orders for NABI buses had been fulfilled.

Design
The NABI CompoBus line uses a model number using the nominal length with a "C" suffix, denoting the composite body, along with the LFW low-floor designator. Each bus has a stamped nameplate with the model number in the format 4xC.nn, denoting the length (40C or 45C) and sequential order number, starting from nn=01.

A composite-bodied transit bus was designed and prototyped in the 1990s under the Advanced Technology Transit Bus (ATTB) Project by Northrop Grumman, jointly sponsored by the United States Department of Transportation, Federal Transit Administration's Office of Research, Demonstration, and Innovation and the Los Angeles County Metropolitan Transportation Authority (LACMTA). The 40-foot ATTB prototypes provided up to 7000 lb savings in curb weight compared to conventional transit buses, and also included a series hybrid powertrain, powered by a Detroit Diesel Series 30 CNG engine; each rear wheel was powered by an in-wheel motor.

When the CompoBus was announced in 1998, NABI hailed it as "the commercial heir to the ATTB" and planned to develop three composite-bodied transit bus products: 30-foot, 40-foot, and 45-foot. The first CompoBus to debut was the 40-foot nominal length (40C-LFW), at the City Transport Exhibit 99 in Toronto, Ontario, on May 25, 1999. A prototype of the 45-foot 45C-LFW, later also known as the Metro 45C, was shown at Anniston on December 1, 2003. The 30-foot 30C-LF was only developed to a prototype stage featuring series hybrid propulsion, but never produced.

Unlike traditional metal-bodied transit buses, which use a steel frame clad with metal skin panels, the structural members, skin, roof, and floor of the CompoBus are built from fiberglass composite laid over a balsa wood core. In total, the structure of the CompoBus uses 80–90 separate components, with just two (the upper and lower main tub sections) responsible for 80% of the entire bus. Metal plates are molded into the structure during assembly to provide mounting points for the engine, transmission, and suspension. The CompoBus is designed to be more resistant to corrosion and low-speed impacts, but are typically not repairable in typical transit operator maintenance facilities if the composite structure is damaged.

NABI licensed the composite molding process from TPI Composites, Inc. in Warren, Rhode Island. The license agreement included access to the patented process, shell prototypes, and development of tooling to produce transit buses. The same process had been used to fabricate the bodies for ATTB, and TPI would go on to produce similar composite bus bodies for the 42-foot battery-electric bus sold by Proterra, Inc.

CompoBus body shells were assembled in Hungary and shipped to Alabama for finishing. Although TPI had been announced as the supplier for the composite bodies in 1998, NABI built a factory in Kaposvár, Hungary expressly to fabricate composite buses; a lawsuit between TPI and NABI was settled amicably in 2001. The Kaposvár factory had two sets of molds (one for the 45C and the other switchable between the 40C or 45C), limiting output to four buses per week, as each of the tub sections occupied a mold for three days at a time.

Because the main structures were assembled in Hungary, NABI applied for a 10-year waiver for Buy America requirements in 2002, stating the goals of the ATTB project could be met, including improved ridership. A two-year waiver was issued instead, and an extension request was denied in 2004. The limited throughput and near-complete assembly at Kaposvar also meant the cost of a CompoBus was up to 30% more than the original quote. The first set of CompoBuses were delivered from 2004 to 2006, and the Kaposvár factory was idled for lack of demand after that.

The factory was restarted in 2008 at the request of LACMTA, but production was stopped again in 2013 with no further orders. LACMTA had been using the 45-foot 45C Compobus, which offered 20% more passenger capacity compared to a 40-foot conventional transit bus, to expand service.

Alternative fuel
In 2003, NABI announced it would deliver three 45C CompoBuses to two southern California agencies for conversion to alternative power. One bus would be sent to the SunLine Transit Agency, who had contracted ISE Research to install a hydrogen fuel cell. Two buses would be sent to the South Coast Air Quality Management District to be fitted with a CNG-powered hybrid electric powertrain. However, the bus that was eventually used by SunLine to demonstrate fuel cell power was a New Flyer HE40LF instead.

Deployment
The first CompoBus orders were placed in November 1999 by Big Blue Bus (40C-LFW) and Valley Metro (45C-LFW), the transit agencies serving Santa Monica, California and Phoenix, Arizona, respectively. 100 CompoBus models had been delivered five years later, by November 2004. Nearly the entire production of 900 CompoBuses were sold to just two agencies: LACMTA (662) and Valley Metro (approximately 200). The majority of CompoBuses produced were the 45-foot 45C models.

Competition

 * Gillig Low Floor
 * Neoplan AN440L
 * New Flyer Low Floor
 * Nova Bus LF Series
 * Orion VI