Sabik LED Signals Ensuring Safety on Finland’s Ring Rail Line
After decades of planning, the Ring Rail Line—linking Helsinki City Center to the Helsinki Airport—was constructed as one of Finland’s most ambitious civil infrastructure projects. Opened to traffic in July 2015, the 18-kilometer-long railway includes 8 kilometers of tunnels and connects key residential, industrial, and commercial zones.
To meet the high availability demands of dense commuter traffic and challenging environmental conditions, Sabik delivered a customized LED signaling solution that played a critical role in ensuring operational safety and reliability.
Background and challenge
The Ring Rail Line connects Helsinki with its airport in Vantaa and intersects two existing radial railway lines. Planning began in the early 2000s, and construction commenced in 2009.
The route includes five operational stations, with provisions for three additional ones, and accommodates a train every 10 minutes in both directions.
With an estimated daily ridership of 16,000 passengers and frequent train intervals, the signaling infrastructure needed to meet extremely high standards. Compounding the challenge were:
- Harsh environmental conditions, including damp tunnels and cold temperatures
- Vibration and air pressure shifts caused by the piston effect in tunnels
- High electromagnetic compatibility (EMC) interference from passing trains
These demands necessitated robust, reliable, and high-performance LED signals designed for long-term, fault-free operation.
Solution – Sabik’s Advanced Combined Signal Lanterns
Collaboration with Thales Transportation System GmbH
In this project, Sabik worked closely with Thales Transportation System GmbH, which supplied an adapted Thales interlocking system tailored for Finnish Interlocking Requirements (FIR). This marked the first large-scale implementation of the Finnish Signaling System 2010.
Development of the “Combined Signal”
To meet the complex signaling requirements of the Ring Rail Line, Sabik developed a new combined signal lantern, integrating:
- Three main signals (red, yellow, green)
- Two flashing distant signals (yellow and green)
- Two shunting signals (white and blue)
All components were housed within a single, compact unit. Each signal module was based on the RSLx100.12 FI(F) LED lantern, featuring a 100 mm light opening. This design reduced the number of separate units needed, simplified installation, and ensured greater durability.
Rigorous Testing and System Integration
The concept for the combined signal emerged as early as 2005. Multiple prototypes with different shapes and configurations were tested in laboratory and field conditions. These tests focused on:
- Optimal luminous intensities and color contrast
- Flashing functionality
- Overall visibility in varying northern light and weather conditions
Integration with the Thales Field Element Controller (FEC) was also tested extensively to ensure seamless operation across various cable lengths and types used in both domestic and export markets.
Outcome – High Reliability and Client Satisfaction
The result was a reliable, fully integrated LED signaling solution capable of withstanding Finland’s demanding environmental and operational conditions. Throughout the project, Sabik’s signals demonstrated:
- High optical performance
- Consistent electrical compatibility
- Resistance to environmental stressors including tunnel humidity, EMC disturbances, and vibration
Client Testimonial
“We are expecting that the system will meet the desired stability in operation. We have seen Sabik products in use previously and believe that Sabik products will be as reliable as before”, says Oliver Ipp, the Sales Manager for International Business at Thales Transportation System Gmbh.
“During the integration of the Sabik signal lanterns into the Thales interlocking system, the easy adaption of the Thales Field Element Controller (FEC) showed the flexibility of the Sabik lanterns. We were able to achieve all the correct optical and electrical parameters with Sabik signals. This was to ensure the reliable operation with Thales FEC with all cable types and lengths which are used not only in Finland but also in our other export countries”
