TrafficInfraTech Magazine Linking People Places & Progress
Monitoring the platform edge
In many stations, the area in front of the platform edge is marked only visually. A compact photoelectric sensor can be used to monitor the platform edge at a length of up to 100m (up to 300m in buildings). People who get too close to the platform edge can be alerted by an audible or visual signal.
Monitoring the area between the platform screen door and the train door
Platform screen doors increase the safety of passengers by preventing falls onto the tracks or an intrusion into the track area. In the outdoors, half-height platform screen doors (APGs) are used for protection and can also be used for partially covered platforms. In the worst case scenario, a person could get stuck in the gap between the train door and platform screen door. If this occurs, the conductor must be reliably notified before departure to prevent the train from proceeding. For this application, a laser measurement sensor, which is mounted above the platform to prevent vandalism, is the ideal solution. Due to the wide measuring range, one sensor can monitor up to three platform screen doors simultaneously. In combination with the Flexi Soft safety controller and cyclic self-tests of the system, safety integrity level SIL2 is achieved. This provides a reliable safety solution even under the most difficult weather conditions.
Case Study
Burning vehicles in tunnel tubes are a serious safety problem. Several hundred meters ahead of the northern Karawanks Tunnel portal, below the old Austrian customs roof, is a Hot Spot Detector. It is used on a daily basis by the Austrian highway operator ASFINAG to ensure a high degree of road safety. The Hot Spot Detector combines measurement data from thermal imaging cameras and laser measurement sensors to detect overheated vehicles in free flow traffic before entering the tunnel. In this way, it makes a significant contribution to preventing vehicle fires in the tunnel. Overheating on the vehicle – so-called hot spots – is localized accurately and, if necessary, signalled as an alarm. By means of an automated diversion process, the connected traffic management system prevents the vehicles from entering the tunnel.
Using laser measurement sensors, every vehicle is measured geometrically, with a 3D model generated and the vehicle classified in one of 28 vehicle classes. Infrared cameras measure the temperature from both sides. The temperature values are combined with
the 3D data of the vehicle to generate a 3D thermal model. Due to this combination, the Hot Spot Detector software is capable of automatically detecting different vehicle components such as load, exhaust system, or wheels, comparing them individually with the temperature threshold values designated for each respective vehicle component.
This Hot Spot Detector has been developed by ECTN AG, a new subsidiary of sensor manufacturer SICK and uses the LMS511 integrated laser sensor measurement sensor.
Monitoring train doors
A smart light grid prevents train doors from closing when an object or person is between the door panels. The slim design of the smart grid and the two options for optical light emission (slim or flat) make inconspicuous, barrier-free mounting on the train door possible. The flexible plastic housing of the smart grid allows use even with curved train doors.
All-clear signal at railroad crossings
At a crossing with full barriers, the train only gets the all-clear signal when it is ensured that there is no large object in the dangerous area between the closed barriers. Use of the laser measurement sensor in conjunction with the intelligent Flexi Soft safety controller is a reliable and cost-effective solution. The traffic controller is relieved of purely visual monitoring since the all-clear signal is generated automatically. The intuitive user interface of the laser measurement sensor makes it easy to precisely adjust the monitoring area to the geometry of the danger area. The level of safety required for crossings is achieved through the dual-channel design and automatic system tests.
Measurement of the train profile
Objects protruding from trains can cause significant damage to the infrastructure. A Railway Profiling System automatically detects clearance violations, which may be caused by a loose tarp, for example. Clearance violations are detected in high resolution at normal speeds regardless of weather conditions. The permitted clearance is adjusted along a wagon based on the distance to the bogies of the wagon to account for cornering. Even very tight turns can be safely navigated.
Christoph SeewaldStrategic Industry Manager
Transport Logistics
SICK