Bombardier Cobra
| Industry | Rail transport equipment manufacturing |
|---|---|
| Predecessor | ABB Cobra division, Schindler Cobra division, SIG |
| Products | Cobra tram |
The Bombardier Cobra is an articulated, low-floor tram operated by Verkehrsbetriebe Zürich (VBZ) in Zürich, produced by Bombardier Transportation. Originally conceptualized by a consortium comprising ABB, Pininfarina, the Schindler Group, and Schweizerische Industrie Gesellschaft (SIG), all manufacturing of Cobra trams has since been carried out by Bombardier.
As Zürich’s pioneering low-floor tram model, the Cobra initially served limited routes but has since expanded to operate extensively alongside both older and newer tram types.
Initial concept
In 1992, a Swiss consortium introduced a proposal for a low-floor articulated tram targeting the cities of Zürich and Basel, with hopes of attracting additional transit operators.
The design, crafted by Pininfarina, featured short modular body sections supported by four-wheel bogies beneath every alternate segment; the intermediate sections without wheels were suspended between these. Each wheel on the bogies could pivot independently without axles, minimizing wear and noise while improving passenger comfort. This axle-less configuration allowed for a continuous low floor, with wheel housings and motors discreetly placed beneath passenger seats.
The running gear was planned to be produced by SIG, electrical components supplied by ABB, and the tram bodies constructed by Schindler Group utilizing synthetic materials.
Prototype
To validate the concept, the consortium transformed Bern tram number 401 into prototype 3000 by installing new running gear and inserting an additional center section. This prototype underwent comprehensive testing in Zürich and Basel, followed by promotional demonstrations in Augsburg and Helsinki before being dismantled in Basel.
Delays and modifications
Changes in policy within Zürich and Basel postponed procurement decisions. Corporate mergers resulted in ABB’s and Schindler’s Cobra divisions becoming part of Bombardier Transportation, while SIG merged into Alstom. Organizational restructuring and downsizing influenced development progress. Due to concerns regarding polymer-based construction, aluminum was ultimately chosen for the tram bodies.
Basel opted for Siemens' Combino over the Cobra design; however, Zürich proceeded with ordering six prototypes from the consortium.
Prototypes in Zürich
In 2001, VBZ introduced six five-section Cobra prototypes (numbers 3001–3006) for trial operations in Zürich. These units were withdrawn following detection of cracks in their drive systems and complaints about noise levels inside and outside the vehicles, leading to further noise mitigation efforts. The media nicknamed the Cobra "rattlesnake" during this period. Since 2002, these prototypes have primarily served lines 4 and 9, occasionally operating on line 6.
After losing market share to Siemens' Combino, the Cobra underwent a redesign that included installation of air conditioning systems.
Production units
Following successful trials, VBZ placed an order for 68 production Cobras (numbers 3007–3074), delivered between 2005 and 2009 to replace almost all rolling stock predating the Tram 2000 series. An option was exercised for an additional 14 units (3075–3088) to support new routes such as Tram Zürich West and Phase 2 of Stadtbahn Glattal.
The original six prototypes were subsequently upgraded to conform with production standards.
Controversy
The introduction of the Cobra low-floor tram encountered significant challenges. Despite being ordered in 1996, its selection over Siemens' established Combino series—already adopted by Basel and Bern—was questioned. VBZ defended its choice citing compatibility with network requirements and carriage length advantages. Notably, from March to April 2010, a seven-section Combino tram from Bern (number 659), known as the "Red Demonstrator," operated on Zürich's line 11, underscoring competitive alternatives.
Early Cobra deliveries in 2001 experienced delays due to corporate changes involving Schindler, Adtranz, and Bombardier. Structural defects and excessive noise led to temporary withdrawal from service. In 1999, Adtranz attempted to substitute Cobra orders with Eurotram vehicles; however, VBZ insisted on maintaining the distinct Cobra design.
By 2002, initial technical issues had been addressed sufficiently to permit fleet expansion to at least 88 trams by 2010. Nevertheless, VBZ announced that future procurements would prioritize established tram models, effectively concluding further Cobra production beyond existing commitments.