The Two Giants of Modern Tram Manufacturing
Walk through a European city with a modern tram network and chances are you're looking at one of two vehicles: an Alstom Citadis or a Bombardier Flexity (now manufactured under Alstom following its 2021 acquisition of Bombardier Transportation). Together, these families have equipped tram networks from Dublin to Dubai, from Melbourne to Montpellier. But they are not interchangeable — each has distinct characteristics, and cities choose between them based on specific operational needs.
The Alstom Citadis Family
The Citadis was introduced in the late 1990s and has gone through multiple generations — Citadis 102, 202, 302, 402, and the newest X05. It is a fully low-floor articulated tram designed for urban street running.
Key Features
- 100% low floor: The entire passenger area is at platform level, maximising accessibility.
- Modular length: Can be configured in different lengths (typically 30–45 metres) by adding or removing modules.
- Catenary-free options: Later versions support battery or supercapacitor operation for heritage zones where overhead wires are unwanted.
- High passenger capacity: A 5-section Citadis X05 can carry over 300 passengers.
- Proven reliability: Decades of service in cities including Paris, Lyon, Barcelona, Dubai, and Melbourne have refined the platform.
Cities Operating Citadis
Paris (all Île-de-France tram lines), Lyon, Bordeaux, Barcelona, Seville, Dublin (Luas), Melbourne, Dubai, Casablanca, and many more.
The Bombardier Flexity Family
The Flexity brand covers several sub-variants — Flexity Outlook, Flexity Classic, Flexity Swift, and Flexity 2 — each targeting different market segments, from street trams to light metro applications. The Flexity 2 is the current flagship street tram product.
Key Features
- Flexible floor options: Some Flexity variants offer partial low-floor layouts, useful for networks with older, higher-platform infrastructure.
- Wide body option: The Flexity 2 comes in wider configurations suited to dedicated tramway alignments with more space.
- High customisation: Bombardier/Alstom has historically offered significant customisation per operator, leading to distinct versions city to city.
- Good energy efficiency: Regenerative braking systems recover energy during deceleration.
- Proven in cold climates: Flexity variants have strong track records in northern European winters in cities like Helsinki and Toronto.
Cities Operating Flexity
Toronto (Flexity Outlook), Blackpool, Brussels, Amsterdam, Helsinki, Ghent, Calgary, and others.
Head-to-Head Comparison
| Feature | Citadis X05 | Flexity 2 |
|---|---|---|
| Floor type | 100% low floor | Low floor (partial in some variants) |
| Typical length | 32–45 m | 30–56 m (varies by order) |
| Catenary-free option | Yes (APS, battery, supercap) | Yes (battery options available) |
| Climate performance | Good (optimised for mild–warm) | Strong in cold climates |
| Customisation | Moderate | High |
| Manufacturer | Alstom | Alstom (ex-Bombardier) |
The Post-Acquisition Landscape
With Alstom's acquisition of Bombardier Transportation completed in 2021, both product lines now sit under one corporate roof. Alstom has indicated it will continue developing both platforms to serve different market needs rather than consolidating into a single product. For operators, this means more choice — but also more complexity when evaluating procurement options.
Which Is Better?
There's no universal answer. The Citadis has a slight edge in pure low-floor accessibility and its proven performance in high-frequency urban networks. The Flexity's advantage lies in its configurability and strong performance in colder, more varied operating environments. Both are world-class vehicles — the best choice depends entirely on the city's specific track geometry, climate, passenger volumes, and infrastructure constraints.