| 摘要 |
<p>Railroad sleepers are replaced by removal of old sleepers over a track length corresponding to the length of a sleeper while ballast is removed to a depth corresponding to the height of new sleepers and is placed beside the track whereafter one or more new sleepers are lowered between the rails and rotated into correct transverse position followed by packing the ballast under the sleeper(s), and the space between adjacent new sleepers is packed with ballast.</p> |
