| 主权项 |
1. A method of detecting a direction of travel of a train on rails of a railroad track, said method comprising: comparing a characteristic of the rails based on a first frequency to the characteristic of the rails based on a second frequency to generate a comparison result, the first frequency being different than the second frequency; and determining the direction of travel of the train based on the comparison result, further comprising: providing a first shunt at a first location along the rails, the first shunt being tuned to the first frequency and the second frequency; providing a second shunt at a second location along the rails, the second shunt being tuned to the first frequency, the first and second locations being on a respective side of a third location; transmitting along the rails a first signal having the first frequency and a second signal having the second frequency; measuring an impedance of the rails in relation to the first frequency; and measuring impedance of the rails in relation to the second frequency. |
