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LOOKING BACK
| 题名： | LOOKING BACK |
| 正文语种： | eng |
| 摘要： | Early trench excavation was often done with a shovel with an elongated dipper stick. The shovel had to dig ahead of itself, and straddled the open trench on timbers or even a very broad-gauge rail chassis. Before trucks came into widespread use, temporary narrow-gauge railroads were often used for jobsite hauling. |
| 出版年： | 2021 |
| 期刊名称： | Roads & bridges |
| 卷： | 59 |
| 期： | 6 |
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