A conveyor installation having a) at least one travel unit that is displaceable along a conveying path and that comprises a carried-along electrical consumer (14, 36), and having b) a busbar that is arranged along the conveying path and that comprises at least one supply conductor line (18, 20, 22) by means of which the travel unit is supplied with power, wherein c) a safety device is provided, that - comprises a, particularly exactly one, safety conductor line that is live during normal operation, - comprises a first safety circuit (K1, K2), which, if necessary, de-energizes the safety conductor line, and - comprises a monitoring means (58, 60; 40), which monitors whether the safety conductor line is de-energized, characterized in that - the safety device comprises a second safety circuit (K1M, K2M), which de-energizes the at least one supply conductor line (18, 20, 22) if the monitoring means (58, 60; 40) detects that the safety conductor line is not de-energized even though the first safety circuit (K1, K2) should have de-energized the safety conductor line, d) and in that the travel unit carries along - a monitoring circuit (32, 34, K10, K11) that detects when there is no more voltage applied to the safety conductor line, and - a stop device (36, 38), which then switches off the electrical consumer (36, 14) of the travel unit and/or blocks movements of the travel unit. a) at least one travel unit that is displaceable along a conveying path and that comprises a carried-along electrical consumer (14, 36), and having b) a busbar that is arranged along the conveying path and that comprises at least one supply conductor line (18, 20, 22) by means of which the travel unit is supplied with power, wherein c) a safety device is provided, that - comprises a, particularly exactly one, safety conductor line that is live during normal operation, - comprises a first safety circuit (K1, K2), which, if necessary, de-energizes the safety conductor line, and - comprises a monitoring means (58, 60; 40), which monitors whether the safety conductor line is de-energized, characterized in that - the safety device comprises a second safety circuit (K1M, K2M), which de-energizes the at least one supply conductor line (18, 20, 22) if the monitoring means (58, 60; 40) detects that the safety conductor line is not de-energized even though the first safety circuit (K1, K2) should have de-energized the safety conductor line, - comprises a, particularly exactly one, safety conductor line that is live during normal operation, - comprises a first safety circuit (K1, K2), which, if necessary, de-energizes the safety conductor line, and - comprises a monitoring means (58, 60; 40), which monitors whether the safety conductor line is de-energized, characterized in that - the safety device comprises a second safety circuit (K1M, K2M), which de-energizes the at least one supply conductor line (18, 20, 22) if the monitoring means (58, 60; 40) detects that the safety conductor line is not de-energized even though the first safety circuit (K1, K2) should have de-energized the safety conductor line, d) and in that the travel unit carries along - a monitoring circuit (32, 34, K10, K11) that detects when there is no more voltage applied to the safety conductor line, and - a stop device (36, 38), which then switches off the electrical consumer (36, 14) of the travel unit and/or blocks movements of the travel unit. - a monitoring circuit (32, 34, K10, K11) that detects when there is no more voltage applied to the safety conductor line, and - a stop device (36, 38), which then switches off the electrical consumer (36, 14) of the travel unit and/or blocks movements of the travel unit.