| 摘要 |
<p>A break in a rail, where two rails (12, 13) extend parallel to each other along a railway line, is detected by connecting the two rails together electrically with two electrical connections (16, 18) at opposite ends of a section of the line, causing electrical currents to flow in parallel along the two rails from a current source (22), and detecting (24) the currents flowing in each of the rails (12, 13). From the two values of current one can find it there is a break in one of the rails (12, 13). The currents may be measured in one of the connections (16). The current source (22) may be DC or low frequency AC, or a coded pulse sequence.</p> |
