When the beagles are running like steam,
When the plough is as sticky as glue,
When the scent is an absolute scream,
And there’s wire in the fence to get through—
What does it mean for "the beagles [to be] running like steam"? "Running like steam" itself seems to be a common enough idiom — it means running quickly — but are we talking about actual beagle dogs here, or is this slang for something else? (This being WWI, it can't be slang for the F-15E.)
I know dogs were used in WWI, but I wouldn't have expected beagles specifically, nor do I understand why an image of beagles running quickly would be a natural opening line for this poem about "our boys at the front."
And on the next line, I suppose the "plough" is a literal plough, maybe for digging trenches or maybe involved somehow with cutting wire; or maybe it's just a mistake for "slough"?
At least I understand (or think I do) the reference to the scent of no-man's-land.