Knorr-Bremse advances rail mobility in Boston – major signaling upgrade reaches final phase
Knorr-Bremse is entering the final phase of a large‑scale rail signaling modernization program in Boston
By the end of 2026, KB Signaling will equip all 26 Red and Orange Line stations with industry‑leading AFTC5 systems
Electronic, software‑based systems architecture is reshaping day‑to‑day rail operations, enhancing safety, reliability, and traffic flow in rail mobility
Progress is already visible across MBTA’s network, with more than 800 AFTC5 systems in service, proving added value under live operating conditions
As a dynamic and evolving metropolitan region, Boston is continuously investing in the modernization of its urban mobility infrastructure – a transformation that Knorr-Bremse actively helps take shape. Continuing to expand its footprint in the fast‑growing railway signaling market, Knorr‑Bremse’s KB Signaling has entered the final phase of a large‑scale signaling upgrade program for the Massachusetts Bay Transportation Authority (MBTA). Since 2019, the company has been equipping the city’s Red and Orange Lines with its AFTC5 (Audio Frequency Track Circuit) technology as part of a multi‑year project valued in the lower triple‑digit million-euro range, with completion scheduled for the end of 2026.
“Around the world, rail networks are entering a new phase of digitalization and modernization – unlocking growth opportunities for advanced signaling and trackside technologies,” says Dr. Nicolas Lange, Member of the Executive Board of Knorr‑Bremse AG with global responsibility for the Rail Division. “For Knorr‑Bremse, signaling and electronics are a cornerstone of our strategic journey toward becoming a Tier 1 systems partner for the entire rail ecosystem. The technologies combine a strong, long‑term business model with a growing demand for high‑performance infrastructure solutions. Projects like Boston illustrate how our technologies translate vision into reality – and how we deliver complex programs with a clear focus on our customers.”
“The modernization of Boston’s Red and Orange Lines – covering 26 stations and now surpassing 800 AFTC5 track circuits in service – represents a major milestone and clearly shows how complex signaling projects can be delivered successfully, step by step, while keeping daily operations running,” says Jeff Baker, Managing Director of KB Signaling. “We are proud to support MBTA as a trusted partner and, together with our local engineering teams, to help advance safer, more reliable, and more efficient rail operations – delivering proven performance even in highly complex urban transit networks.”
Technology that delivers immediate value
Beyond Boston, the electronic AFTC5 platform is already helping to shape the next chapter of rail modernization in major metropolitan areas across the United States, including Los Angeles and Chicago. In these cities, it forms part of long‑term transformation programs that are progressively replacing decades‑old, often analogue trackside equipment with electronic and intelligent architectures – allowing networks to evolve step by step, without disrupting daily operations or requiring full infrastructure replacement.
Foundation of modern signaling technology
The AFTC5 Audio Frequency Track Circuit marks the transition from traditional solutions to a fully digital generation and forms a key foundation of modern signaling systems. By transmitting audio‑frequency signals directly through the rails, it enables reliable train detection and supports the data‑based exchange of safety‑critical information such as train speed commands. This digital capability ensures clearly defined train positions, dependable track clearance, and safe train separation at all times – creating the basis for safe, efficient, and high‑performance rail operations in one of the United States’ most important urban rail systems.