UK: Geotechnical contractor Geobear has been granted a UK patent for its track strengthening method for use in transition zones.
Transition zones are found at the change from flexible formations like ballast to rigid foundations like concrete. These abrupt changes can cause differential settlement, leading to track faults, damage to sleepers, rails, and, in extreme cases, derailment.
Geobear’s method creates a gradual change in track bed support by using geopolymer injections beneath the existing tracks. The company says this tackles longstanding challenges in transition zones and enhances track stability without disrupting services.
Conventionally, contractors excavate the track section approaching the stiff foundation to build a transitional wedge of high-compaction material beneath the ballast. However, Geobear believes this method is both labour-intensive and disruptive, necessitating deep excavation and complete track disassembly, often resulting in service interruptions lasting up to four days.
‘Our patent offers a transformative solution to this entrenched challenge in railway infrastructure’, explained Mohamed Wehbi, Technical & Business Development Director at Geobear and the inventor of the patented approach. ‘Through targeted geopolymer injections beneath the existing track, we establish a carefully calibrated stiffness gradient that intensifies as it nears the foundation transition.
Wehbi says that Geobear’s approach does not require lengthy possessions of the railway to install. ‘The process can be completed in two to four short night shifts without interrupting train services, making it a practical, non-disruptive solution for rail operators’, he says.
The company adds that track geometry faults, often caused by settlement at transition zones, account for 10% of Network Rail’s total maintenance spend. ‘The patent not only minimises track deterioration but also supports predictive maintenance strategies, enhancing repair effectiveness and reducing service disruptions’, explains Geobear’s Director of Infrastructure Richard Holmes. ‘By keeping lines operational during works, we can prevent lost revenue from cancelled services and maintain passenger trust.’
