AIVR STREX

What is it 

AIVR STREX is a rail infrastructure monitoring solution that captures video of the trackside environment; ‘Strex’ being an abbreviation of structural examination.

Currently in operation on the UK rail network, it is designed to supplement Forward Facing Video (FFV) imagery, helping asset managers and Track Maintenance Engineers (TMEs) to monitor the condition of assets such as structures, signals and Overhead Line Equipment (OLE).

Why it matters

The condition of civils and structures has traditionally been monitored through Basic Visual Inspections (BVI), in which track patrollers walk the line to make a visual check of asset condition. These inspection techniques have significant safety, capacity, consistency and coverage drawbacks. For example, the track possessions necessary for daytime physical inspections impact on services. This made physical inspections beyond the annual rate required by Network Rail standards difficult to justify without evidence of asset degradation.

AIVR STREX allows asset managers or track maintenance engineers to make remote inspections of trackside assets, providing up-to-date evidence that helps them to make decisions about maintenance.

These capabilities supplement annual physical inspections required by Network Rail standards, and may trigger additional physical inspection, and/or repair or refurbishment of assets by TMEs.

Where and when it’s used

AIVR STREX was developed by tech firm One Big Circle, based in Bristol, UK. It was first permanently installed on the Class 153 Visual Inspection Unit Fleet in 2024. It is a proven technology, with a Rail Industry Readiness Level of 9.

How it works

AIVR STREX features a pair of outward-facing cameras mounted in robust enclosure on the front of trains. These capture both sides of the track simultaneously, enabling remote inspection of features and assets.

Data is transmitted from the train-borne sensors such as STREX via 4G/5G to AIVR’s data centre in the Cloud, where it is made rapidly available to users of the AIVR Platform. Imagery may then be viewed on the AIVR Platform.

STREX software detects and identifies assets such as stanchions, signals, speed boards and overhead line equipment (OLE) features, such as droppers. In addition, OCR (Optical Character Recognition) reads Asset ID plates visible in STREX footage and records and geolocates those assets.

On the AIVR Platform, users can annotate assets and view past images of them for comparative purposes.