IN Brief:
- DB InfraGO has approved Saft Flex’ion LFP systems for Germany’s digital interlocking programme.
- Initial batteries are being installed at trackside infrastructure hubs in the greater Stuttgart area.
- The systems provide immediate backup power for safety critical signalling and control infrastructure.
Saft has been selected by DB InfraGO to supply lithium iron phosphate battery systems for Germany’s digital railway interlockings, with initial Flex’ion units being deployed around Stuttgart.
DB InfraGO, Deutsche Bahn’s infrastructure company, selected the equipment following qualification work covering safety, reliability, performance and long term operating value. Saft says the approval makes it the first industrial LFP battery supplier validated for deployment within the digital interlocking programme.
The batteries are being installed at trackside infrastructure hubs supporting the new interlockings. Their role is continuity power rather than railway traction, keeping signalling and control equipment operating when the normal electricity supply is interrupted or lost.
Digital signalling places greater reliance on electrically powered control, communications and field equipment distributed across the railway. Loss of supply at a critical point can therefore affect systems responsible for train movements, points, signals and level crossing equipment even when the traction power system itself remains available.
Saft’s installation uses its Flex’ion lithium ion platform with LFP chemistry. The manufacturer positions the system for critical infrastructure applications requiring compact installation, limited routine maintenance and long service life, with the battery architecture designed around high availability rather than mobile energy density.
That operating profile suits fixed signalling infrastructure. Backup systems may spend most of their service life charged and waiting, but they have to respond immediately when the incoming supply falls outside acceptable limits. Cell condition, battery management, protection, monitoring and DC distribution therefore need to remain ready without relying on frequent discharge cycles to demonstrate availability.
The digital interlocking architecture also changes where those backup systems are required. Traditional signalling arrangements often concentrated control equipment in local signal boxes, while newer systems distribute parts of the control and field interface through trackside equipment linked by digital communications.
Track field concentrators form part of that infrastructure, connecting central systems with equipment such as signals, points and barriers. A national deployment can consequently involve large numbers of electrically supplied field locations, turning continuity power into a repeatable infrastructure requirement rather than a small number of isolated installations.
The battery duty is dominated by dependable standby behaviour and rapid transfer rather than the long-duration energy shifting associated with grid scale storage. Control equipment must see no unacceptable interruption while the installation changes from normal power to battery supply, and the DC system must remain within the voltage and protection limits of the connected signalling equipment.
Flex’ion Gen 2 has been developed for short-duration, high-power backup applications and supports remote monitoring and modular installation. Those characteristics can reduce the physical and maintenance burden at constrained trackside sites, where equipment access and intervention windows may be more restrictive than in conventional industrial buildings.
Environmental conditions also shape the installation. Railway infrastructure is distributed across outdoor and semi-protected locations exposed to temperature variation, vibration from traffic and differing maintenance regimes. Battery systems have to be engineered around those conditions while retaining the diagnostics needed to identify deteriorating modules before a standby event.
The DB InfraGO programme gives Saft an application at infrastructure scale rather than a single demonstration. Qualification is important because signalling equipment sits within a safety critical system, so electrical performance has to be considered alongside maintenance procedures, fault behaviour and the wider assurance requirements imposed by the railway.
The deployment is distinct from Saft’s LFP traction and auxiliary railway battery platforms launched earlier this week. Those products are intended for onboard duties, whereas the DB InfraGO programme uses fixed batteries to protect trackside signalling and control infrastructure.
Separating the applications avoids treating railway electrification as a single battery market. Rolling stock propulsion, onboard auxiliaries, station systems, telecommunications and signalling each impose different voltage, power, energy and safety requirements even where they share LFP chemistry and battery management technologies.
The first Stuttgart installations will now provide an operating reference for Flex’ion within Germany’s digital interlocking programme. Wider deployment will depend on DB InfraGO’s modernisation programme and the requirements of individual infrastructure packages, but the qualification establishes an approved battery architecture that can be repeated as additional digital signalling sites are delivered.
