System for transporting objects under controlled atmosphere comprising tubular sections connected together in a leak tight manner by their first ends, each tubular section, each section comprising a guide track for a trolley, each guide track comprising a first and a second end, the first ends of the guide tracks being opposite and separated from each other by a given distance. The transport system also comprises a spanning element rotationally hinged on a first end of the guide tracks around an axis orthogonal to a direction of displacement of said guide track. The spanning element is moveable between a raised position and a spanning position in which the guide tracks are connected enabling the passage of the trolley.