A monitoring device arrangement is disclosed that may comprise a mounting rail and at least two fixed monitoring devices. The fixed monitoring devices may each being mounted on a respective holder. The holders may be arranged on the mounting rail. Each holder may include a lock device that locks the holder in a determined position on the mounting rail. The lock device may be releasable to allow sliding repositioning of the holder on the mounting rail.

A self-propelled security system on an adjacent to a fence track, equipped with at least one imaging sensor and wherein the rail track on which the system's movable payload is propelled and the movable payload are both exposed to the fence side, and an anchoring means for anchoring, from time to time, the movable payload, and replacing the payload's battery with a new one within the anchoring means.

A monitoring device arrangement is disclosed that may comprise a mounting rail and at least fixed monitoring devices. The fixed monitoring devices may each being mounted on a respective holder. The holders may be arranged on the mounting rail. Each holder may include a lock device that locks the holder in a determined position on the mounting rail. The lock device may be releasable to allow sliding repositioning of the holder on the mounting rail.

A monitoring device arrangement is disclosed that may comprise a mounting rail and at least two fixed monitoring devices. The fixed monitoring devices may each being mounted on a respective holder. The holders may be arranged on the mounting rail. Each holder may include a lock device that locks the holder in a determined position on the mounting rail. The lock device may be releasable to allow sliding repositioning of the holder on the mounting rail.

A monitoring device arrangement is disclosed that may comprise a mounting rail and at least two fixed monitoring devices. The fixed monitoring devices may each being mounted on a respective holder. The holders may be arranged on the mounting rail. Each holder may include a lock device that locks the holder in a determined position on the mounting rail. The lock device may be releasable to allow sliding repositioning of the holder on the mounting rail.

A monitoring device arrangement is disclosed comprising a mounting rail, and at least two fixed monitoring devices, said fixed monitoring devices each being mounted on a respective holder, said holders being arranged on said mounting rail, wherein each said holder comprises a lock device locking said holder in a determined position on said mounting rail, and wherein said lock device is releasable to allow sliding repositioning of said holder on said mounting rail.