Abstract: The present invention relates to a system for the vehicular transportation of a lock-equipped cassette (1) for valuable documents between a first station, e.g. a bank or a post office, to a second station. The cassette (1) is intended to be kept in a cassette holder or rack (2) in the first station and the second station, and also in the transporting vehicle. The cassette is provided with an electronic circuit (R1,22) which is characteristic to the cassette concerned and which is arranged to co-act with a controlling activating circuit (M1). When the cassette (1) is lifted from its cassette holder or rack a clock circuit located in the cassette is activated and, unless the cassette is replaced in a cassette holder within a predetermined time, causes an alarm to be activated, this alarm being an acoustic alarm, a device for generating smoke within the cassette, releasing a dye onto the valuable documents contained in the cassette, etc.