It depends. On all our old and new tram models the upper part of the window can be cracked open. Not fully, just enough for the breeze and fresh air to get in. Buses have fixed windows that can’t be opened. Trains — at least in my home country — vary: old ones you can usually slide the entire window open in the hallway(?), but the cabins, IIRC, have the same mechanism like the trams; new ones have fixed windows, IIRC, but they are also air-conditioned, so it’s not a problem.
It depends. On all our old and new tram models the upper part of the window can be cracked open. Not fully, just enough for the breeze and fresh air to get in. Buses have fixed windows that can’t be opened. Trains — at least in my home country — vary: old ones you can usually slide the entire window open in the hallway(?), but the cabins, IIRC, have the same mechanism like the trams; new ones have fixed windows, IIRC, but they are also air-conditioned, so it’s not a problem.