Onboard Monitoring and Control – Wireless Sensor Networks Systems Integration
A practical wireless train network (WTN) for freight trains is defined. A hybrid technology network utilizing ZigBee within each railcar and WiFi to create an ad hoc train network is researched. Motes and PAN-coordinators have been fabricated for demonstration testing. Network software were developed and embedded for testing. A specialized wheel bearing sensor was developed; it contains a thermistor, a 3-axis accelerometer, and a microphone. The sensor components were fabricated and the firmware has been developed. Raw data can be acquired or the fast Fourier transforms can be compared to thresholds for alerts. A demonstration was designed and built to activate and deactivate electronically deployed hand brakes developed by Sharma and Associates. This can enable the activation of hand brakes remotely from the locomotive for every railcar. The WTN was developed to self-initiate as the train leaves the departure yard. Activation is based on the attachment of the End-of-Train device and forward acceleration in each railcar. WiFi beacons from the gateway are detected by each railcar in series as they accelerate forward. That timing determines the railcar order. Direction of forward accelerations determines the railcar orientation. The data are automatically assembled as the train departs and is uploaded to the enterprise.