Table 1 Variations of thresholds,... | Emerald Publishing

Table 1

Variations of thresholds, spacing and alarm logic in different regions

Region	Thresholds	Spacing	Alarm logic
Europe	ΔT 40–60°C + Absolute 100–120°C (ambient corrected)	60–100 km (denser near tunnels, hazmat routes)	Multi-level (warning/alert/critical), OCC rulebooks
North America	Absolute ∼105–115°C (prescriptive FRA rules)	40–65 km (25–40 miles) prescriptive spacing	Binary stop/inspect at next siding for hotbox
India	Mixed absolute/differential, integrated into EHMS	Dense corridors, centralised coverage (>900 sites)	EHMS: multi-level alarms integrated with OCC
China	Adaptive + AI classifiers, multi-spectral IR	Strategic siting on HSR and freight corridors	AI-enhanced, multi-sensor fusion, digital twin pilots
Australia	Absolute + differential, tuned for >30 t axle loads	Close spacing (30–50 km) on heavy-haul corridors	Multi-level, combined HABD + acoustic/vibration pilots

Region	Thresholds	Spacing	Alarm logic
Europe	ΔT 40–60°C + Absolute 100–120°C (ambient corrected)	60–100 km (denser near tunnels, hazmat routes)	Multi-level (warning/alert/critical), OCC rulebooks
North America	Absolute ∼105–115°C (prescriptive FRA rules)	40–65 km (25–40 miles) prescriptive spacing	Binary stop/inspect at next siding for hotbox
India	Mixed absolute/differential, integrated into EHMS	Dense corridors, centralised coverage (>900 sites)	EHMS: multi-level alarms integrated with OCC
China	Adaptive + AI classifiers, multi-spectral IR	Strategic siting on HSR and freight corridors	AI-enhanced, multi-sensor fusion, digital twin pilots
Australia	Absolute + differential, tuned for >30 t axle loads	Close spacing (30–50 km) on heavy-haul corridors	Multi-level, combined HABD + acoustic/vibration pilots

Source(s): UIC (2024), ProRail (2020), RISSB (2022), Indian Railways (2022), CARS (2019)