Abstract: A wall plug (1) comprises a body portion (2:30:30a:40) and a rotatable portion (3:31:31a:41) received therein, the rotatable portion having a passageway (13:32:32a:42) therethrough which is offset both from the axis of rotation of the rotatable portion and also from the axis of the passageway in the body portion in which the rotatable portion is received. The rotatable portion can thus be angularly adjusted to a selected position of offset between its passageway axis and the axis of the passageway in the body portion to compensate for a hole drilled to receive the wall plug being out of position. The offset lead-in offered by the passageway in the rotatable position makes screw engagement easier than with a wholly misaligned wall plug. Means (16, 17) are provided for retaining the rotatable portion in its selected adjusted position.

Abstract: A passenger-carrying vehicle (for example a bus) in a passenger transport system is equipped with a ticket reader (18) capable of optically reading information printed on a ticket (10) in bar-code and determining whether or not the ticket is valid. A ticket-printer (16) is provided for issuing bar-coded tickets, and both the reader (18) and the printer (16) are microprocessor-based and associated with a memory (14). Fare-table data is stored in the memory (14a), for reference by the ticket-issuing means, data is stored in the memory (14b) for reference by the ticket-checking means, and both the issuing means and the checking means can communicate information to the memory (14c) and (14d) to enable data concerning tickets handled to be stored for subsequent retrieval for management purposes.