supply of surface roughness measuring instrument for rail grinding machine.surface roughness measuring instrument for rail grinding machine.,surface roughness measuring instrument for rail grinding machine.it is a pocket-size d portable instrument measures the roughness of the rail .it should have lcd display that shows surface ro ughness parameter ra (arithmetical mean roughness value), rz (mean roughness depth), rms (maximum roughness depth) (rq) and rt (total height of the roughness profile), operates on various surfaces, not o nly flat but also outer cylinder, outer cone, grooves, and recesses greater than 80 x 30mm.asme b46.1-20 19,iso 4288:1996 or is 15263:2002 [ warranty period: 30 months after the date of delivery ] ]