On page 11 of the Fall 2005 S.P. Trainline magazine is a picture (early 1960s) of German dielsel -hydraulic locomtives passing by a (cement?) plant east of Tehachapi Pass, California. In the foreground, there is a long rail to the side of the tracks, with tie plates leaning against it. I speculate the rail is welded, and will replace the rail on track adjacent to it. Am I right?
Most likely.
Yup. Could also be rail that had just been replaced.
Nick