It describes a crowded space, the soldiers standing shoulder to shoulder and whatnot. It reads like soldiers on the shores of Normandy or something similar but, at the end, it is revealed that it was actually describing the soldiers inside the Trojan Horse.
This sounds like After Ten Years, an unfinished novel by C.S. Lewis included in The Dark Tower and Other Stories. The first chapter taken alone matches your description perfectly.
For several minutes now Yellowhead had thought seriously of moving his right leg. Though the discomfort of his present position was almost unbearable, the move was not lightly to be undertaken. Not in this darkness, packed so close as they were. The man next to him (he could not remember who it was) might be asleep or might at least be tolerably comfortable, so that he would growl or even curse if you pressed or pushed him. A quarrel would be fatal; and some of the company were hot-tempered and loud-voiced enough. There were other things to avoid too. The place stank vilely; they had been shut up for hours with all their natural necessities (fear included) upon them. Some of them - skeery young foold - had vomited. But that had been when the whole thing moved, so there was some excuse; they had been rolled to and fro in their prison, left, right, up and (endlessly, sickeningly) down; worse than a storm at sea.
That had been hours ago. He wondered how many hours. It must be evening by now. The light which, at first, had come down to them through the sloping shaft at one end of the accursed contraption had long ago disappeared. They were in perfect blackness. The humming of insects had stopped. The stale air was beginning to be chilly. It must be well after sunset.
And so, breathing deep and stretching their limbs, they all stood by the feet of the great wooden horse with the stars above them, and shivered a little in the cold night wind that blew up the narrow streets of Troy.