Double-decker trains are a common sight across Europe, designed to maximize passenger capacity on busy commuter and high-speed routes without increasing train length. Some of the most famous examples include the TGV Duplex in France, which operates at speeds up to 320 km/h, and the InterCity (IC2000) in Switzerland, known for its panoramic upper-deck views of the Alps. In Germany, the Deutsche Bahn (DB) Doppelstockwagen are the backbone of regional travel, often featuring bike storage on the lower level. The Netherlands uses the VIRM and DDZ trains for its dense Intercity network. These trains typically place the entrance at platform level, with stairs leading to a quiet upper deck for long-distance travelers and a lower deck for shorter hops or those with heavy luggage. In 2026, these trains are prized for their "High-Fidelity" space efficiency, allowing operators to move twice as many people through congested corridors like Paris-Lyon or Amsterdam-Utrecht while maintaining high-fidelity comfort and stability.