mile a minute

今日取り上げる表現は初めて見ますが、意味は文脈から容易に分かります。Net Forceの作者はこの表現が好きなようで、一度ならず使っています。最初は次の場面にありました。
Roddy was surrounded by what appeared to be a large number of media people--some of them carrying their press credentials visibly, others simply listening, though doubtless every word Roddy said was going into a recording site somewhere else and would be all over the news tomorrow. Roddy was not missing the oppotunity. He was talking a mile a minute, and the media people were hanging on his every word.
辞書にこの表現の説明があるか調べます。
・McGraw-Hill Dictionary of American Idioms and Phrasal Verbs: Fig. very fast. (*Typically: go ~; move ~; talk ~; travel ~.) She talks a mile a minute and is very hard to keep up with.
・Urban Dictionary: acting rapidly in a highly agitated way: Stop talking a mile a minute and calm down.