Railroad vehicle for measuring the geometrical parameters of railroad track

In a railroad vehicle for measuring by optical means the geometrical parameters of a track comprising a first rail and a second rail, the vehicle moving on said track and including a first bogie (10) and a second bogie (20) each of said bogies having two main axles, the improvement wherein each of the first and second bogies includes a third axle (13, 23) with independent wheels, and said vehicle further includes:

• a third bogie (30) mounted to the vehicle between said first and second bogies and comprising two main axles (31 and 36), capable of moving relative to each other about an axis passing through their centers, and a third, central axle (39) with independent wheels, placed between said two main axles of said third bogie;
• three pairs (51 and 53;
• 62 and 63;
• 72 and 73) of optical proximity meters disposed on respective ones of the three independent-wheel axles (13, 23 and 29), each proximity meter including an emitter and a receiver placed so as to look at the inside faces of the first rail (2) and the second rail (3) respectively;
• first and second pairs of optical distance gauges whose receivers (81 and 82;
• 81A and 82A) are disposed head-to-tail in pairs at the ends of the central axle (39) of the third bogie (30) and whose emitters (91 and 92;
• 91A and 92A) are disposed at the ends of the independent-wheel axles (13 and 23) respectively of the first (10) and second (20) bogies;
• and
• a third pair of distance gauges whose receivers (93 and 93A) are placed at the ends of one (31) of the main axles of the third bogie (30) and whose emitters (94 and 94A) are disposed at the ends of the other (36) axle of the third bogie (30).