These trains are called 'T-trains' by the train crew since the last letter of the train number is T. (The last letter of the train numbers for Rapid trains between Takatsuki Station and Kyoto Station is M for weekdays and K for weekends.
乗務員などは列車番号の末尾を取って「T電」と呼ぶ場合がある（高槻～京都間快速運転の場合の列車番号末尾は平日M、休日Kである。