Bahnhof AB: Pionen Data Center

Located at Renstiernas gatan 35/37 in the Södermalm district of Stockholm, Sweden, Pionen Data Center is operated by Bahnhof AB. 

The facility is built in a former Cold War era civil defence shelter, approximately 30 metres beneath the granite bedrock of the “Vita Bergen” (White Mountains) in central Stockholm — a location chosen for its extraordinary security, structural resilience and discreet urban footprint. 

Strategically, Pionen offers colocation, hosting and interconnection services in one of Scandinavia’s key digital infrastructure hubs. Its subterranean design combined with high-density connectivity and green-energy driven operations make it a standout facility in the Nordic data-centre market.

⚙️ Facility Highlights

• The facility resides under 30 m of solid granite bedrock, shielding it structurally and providing exceptional protection. 
• The entrance is secured by a steel door up to 40 cm thick and reachable only through a controlled access tunnel — originally designed for nuclear-bomb resilience. 
• Redundant power and cooling infrastructure: For example, diesel backup power via submarine-engine-derived units (MTU Maybach) and advanced cooling systems; the facility also incorporates waste-heat reuse with district-heating integration. 
• High availability design: The site offers robust internal redundancy including UPS systems, dual cooling loops and secure environmental controls. 
• It is marketed as a carrier-neutral colocation / hosting environment. 

🔐 Security & Compliance

• The facility is certified to Swedish protection class 3 (Skydsklass 3) under SSF 200 and alarm class 3 (Larmklass 3) under SSF 130. 
• Uses 24/7 CCTV, access logging (with retention of at least six months of access records) and intrusion detection systems.
• Fire detection and suppression: Very-early smoke detection (VESDA) systems, inert-gas fire suppression (e.g., Novec 1230) in server halls.
• The operator emphasizes 100% green electricity usage and energy-efficient infrastructure as part of its environmental compliance approach. 

🌐 Connectivity & Carrier Access

• Situated in Stockholm’s fibre- and carrier-dense region, Pionen benefits from multiple physically diverse fibre entry paths — offering excellent connectivity and low latency across the Nordics and wider Europe. 
• As a carrier-neutral site, it supports interconnection with a broad set of network providers and cloud platforms. 
• The colocation environment supports flexible connectivity options, from rack-level to full suite deployments, leveraging the operator’s in-house network and peering ecosystem.

💼 Who It Serves

• Enterprises and cloud providers requiring ultra-secure, high-availability infrastructure in a strategic Nordic market.
• Network carriers, telecommunications providers and content delivery networks that need a resilient interconnection node with diverse fibre access.
• Organisations focused on compliance, security and business continuity (e.g., financial services, government, research institutes) looking for a subterranean, highly controlled environment.
• Sustainability-driven enterprises seeking data-centre solutions with green-energy sourcing and waste-heat reutilisation functionality.