Ok, thanks. This is a very unusual word. It comes from the verb 'to swarm', which is usually used to describe how bees and other insects gather together in big groups. You can also use it figuratively to describe large groups of people moving around. That's the meaning - now the grammar. In the past it was normal to create adjectives and adverbs by adding 'a' to a noun or a verb. Words which still exist today formed in this way are 'awake' or 'asleep'. Someone who is sleeping can be described as 'asleep', for example. 'Aswarm' is like this - it means that travellers were swarming around the station like bees around an apple tree.

We use "swarm" in reference to a group of flying or crawling insects. The adjective can be "aswarm", or more commonly "swarming". Notice that "with" follows the adjective in both cases.

"aswarm" comes from the word "swarm" (which means "a large or dense group of insects, especially flying ones"). So in this case, a swarm is used figuratively meaning a large group of something and everything in that group is moving back and forth in all directions, like a swarm of insects. So the sentence means: The station was full of travelers who were moving in all directions.

Aswarm means crowded.

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