Abstract: A testing machine includes a pair of spaced side-by-side rails spanned by a carriage and opposite thereto a piston/cylinder mechanism between each rail and an associated crosshead. A wire cable, sling or the like is connected between the carriage and the crosshead and when the pistons of the piston/cylinder mechanisms are forcefully extended from the cylinders the sling is brought under tension loading upwardly to 3,000,000 lbs. Each side rail is formed of a plurality of sections with each section being defined by relatively long metal rail members joined by tubes and carrying studs and a first series of rebars. A second series of rebars spans a joint between adjacent rail sections. The metal rail members of adjacent sections are spaced from each other to define a gap therebetween. Concrete is poured into the sections to eventually surround, embed and unitize the sections upon subsequent solidification of the concrete.