The need for advanced solutions for access and intervention in pipeline networks is steadily increasing, given their importance in urban and industrial infrastructure. Pipelines are used in essential applications such as potable water transport, sewage systems, HVAC networks, industrial gas distribution, chemical installations, and ventilation systems. This paper proposes an autonomous mobile robot capable of navigating and performing tasks inside circular rectilinear pipelines. It uses two gear-based fixing mechanisms located at the ends of the robot’s body. The motion of the mobile robot is a sequential movement: one end is fixed to the pipe wall via an electrically actuated mechanism, while the other is released. Two linear actuators, mounted between the two ends, allow the robot to extend and retract, ensuring its movement.