The floors at the Santa Fe locomotive repair shops in San bernardino (R.I.P.)were 4" sq. wood blocks standing on end and tightly pressed together. This was especially true in the machine shops where damaged blocks were replaced. Other areas had the blocks replaced with concrete as time moved on. Rubber "Stress Mats" were installed for the machine operators. The pits were all concrete with wood covers and wood or steel grating on the floors. Steel or concrete replaced wood in most cases as time moved on.