The speaker stands in a shuttered factory and asks a string of pointed questions: why is there no memorial here, when towns honor soldiers and battlefields? The poem compares factory work to war. Workers "ground down their lives," and the imagined veterans would return with "pride mingling with grief," clutching flags that were, bitterly, made in China. That detail hints at why the jobs disappeared.
The tone is angry but also tender. Words like "a mass unmanning" suggest that losing work stripped people of dignity as well as income, and the machines, sold for scrap, are given a kind of grim respect as "great steel taskmasters." The speaker counts themselves among the "trespassers," as unwanted as weeds and sparrows, which shows how forgotten the place is. The final question is quietly moving: no one wants to remember "which parts were assembled here / & where they fit." The mood is elegiac and indignant, a plea that ordinary labor deserves to be remembered as much as any battle.