[Arthur will usually look for a compartment by himself, though he (usually) won't object to company. As it is, he doesn't have any yet, and is sitting by himself next to the window, looking out of it as the train moves through the countryside. He's not yet changed into his uniform, wearing a white t-shirt and a pair of slightly worn jeans, and has a small bag next to him, between himself and the side of the train.

Anyone who has seen Arthur on the train before will know that he always brings a large amount of sweets with him, and he's currently picking from a bag of what are most certainly Muggle sweets - a gift from his aunt

Generally, he's not fussy about sharing. It makes for a good conversation starter]