for measuring movement of the track or of the components thereof under rolling loads, e.g. depression of sleepers, increase of gauge

Full Title

Applications of measuring apparatus or devices for track-building purposes (apparatus on locomotives or cars to indicate or record bad track sections B61K9/00; measuring angles, linear dimensions, or irregularities in general G01B, G01C) > for measuring movement of the track or of the components thereof under rolling loads, e.g. depression of sleepers, increase of gauge