The Transformative Power of LiDAR on the railway industry

Frequently Asked Questions

• Why does radar struggle to detect stationary trains or rail vehicles?

  Radar sensors use the Doppler effect to distinguish objects from background clutter, which means stationary or slow-moving targets produce little return signal and are easily suppressed by the sensor's filtering logic. This is a fundamental physics constraint, not a calibration issue. LiDAR, by contrast, measures direct time-of-flight of laser pulses against any surface regardless of whether it is moving, making it reliable for detecting stopped trains, freight cars, or personnel standing on or near the track. This is why infrastructure-based LiDAR deployments, such as those Outsight operates across SNCF Gares and Connexions stations in France and SICE/FGV train stations in Spain, can continuously track stationary and slow-moving rail vehicles with consistent accuracy that radar cannot match.

• Can LiDAR work inside tunnels where cameras lose visibility?

  LiDAR is an active sensor: it emits its own laser pulses and measures their return, so it does not depend on ambient light at all. Inside a tunnel, where illumination is low and camera performance drops sharply, a LiDAR sensor continues to produce full-density 3D point clouds with no degradation. This makes it particularly suited to the rail environment, where tunnels, covered platforms, and night operations are routine rather than edge cases. Outsight's infrastructure-based approach applies exactly this principle across rail deployments, including SNCF Gares & Connexions stations in France and SICE / FGV train stations in Spain, where the SHIFT platform processes 3D LiDAR data in real time regardless of lighting conditions.

• How accurate is LiDAR for measuring the speed of a passing freight train?

  A 3D LiDAR sensor tracks the successive position of a target across frames at a known time interval, yielding velocity derived from displacement rather than Doppler shift. This approach works equally well for fast-moving rolling stock and for slow shunting maneuvers. Combined with appropriate perception software, frame-to-frame velocity estimates can reach centimeter-level spatial precision, which is sufficient for speed-limit compliance checks and impact-risk calculations at level crossings. Outsight's infrastructure-based pipeline processes each LiDAR frame end-to-end in under 50 milliseconds, meaning velocity readings are available in near real-time without relying on sensors mounted on the train itself, a key advantage in mixed-traffic rail environments where consistent onboard instrumentation cannot be assumed.

• What rail safety applications beyond passenger flow is LiDAR used for?

  Beyond passenger flow, rail operators deploy infrastructure-mounted LiDAR for track intrusion detection (people or objects on the live rail), level-crossing monitoring, platform-gap hazard alerts, and freight volume measurement in yards and loading bays. Outsight's Infrastructure-based Physical AI approach applies directly to these scenarios: by positioning LiDAR in the fixed infrastructure rather than on rolling stock, the SHIFT platform can monitor platforms, tunnels, and crossings continuously in real time, without relying on lighting conditions or line-of-sight limitations that affect cameras and radar. The wider rail supply chain, including freight and loading operations, also uses LiDAR for vehicle presence detection and load monitoring. All of these applications share the same core sensing requirement: reliable 3D data at long range regardless of weather or ambient light.

• How does LiDAR sensor range compare to camera range in open rail environments?

  In open outdoor conditions, high-end 3D LiDAR sensors can reliably detect large objects such as freight cars or vehicles at ranges exceeding 500 meters. Camera-based detection at comparable distances depends heavily on resolution, focal length, and lighting, and degrades sharply in haze, rain, or direct sun glare, all of which are common in outdoor rail corridors. Long-range LiDAR coverage allows a single sensor to monitor large stretches of track or open yard without requiring a dense sensor array. Outsight's infrastructure-based approach takes advantage of this range characteristic by processing LiDAR point clouds through its SHIFT platform in real time, enabling continuous monitoring of station approaches and open trackside zones across deployments such as SNCF Gares et Connexions stations in France.

• Does a hardware-agnostic LiDAR software approach matter for rail procurement?

  Rail infrastructure projects typically span decades and involve multiple procurement cycles, different contractors, and sensor technology refreshes. A software platform that is hardware-agnostic and compatible with sensors from multiple manufacturers protects the operator from vendor lock-in and allows each project segment to use the sensor best suited to its range, resolution, and environmental requirements. Outsight's SHIFT platform, for example, supports multi-vendor LiDAR hardware across Hesai, RoboSense, Ouster, Velodyne, and Seyond, which means rail operators can mix sensor models across a single deployment to balance performance and cost. This approach is already in use across SNCF Gares and Connexions stations in France and SICE/FGV train stations in Spain, demonstrating that hardware-agnostic software is a practical procurement consideration rather than a theoretical one.