Two short lines, and a whole picture. The poem seems to describe heavy trucks that are no longer moving, perhaps parked, stalled, or standing in the cold, and it sees them as mammoths frozen in glaciers. The comparison works because of size and weight: a big truck and a mammoth both feel massive, powerful, and slow to stir.
The word "now" matters a lot. It suggests a change, as if these machines were once roaring and busy and have gone still. The speaker doesn't say how they feel outright, but the tone sounds quietly awed, maybe a little wistful. There's a sense that something huge has been stopped and preserved, like a relic.
The mood is cold, hushed, and strangely ancient. By linking modern machines with Ice Age animals, the poem makes the present feel like it could already belong to the distant past, and it leaves us wondering what else might one day be left frozen in time.