with all due respect for ima-swinger, ...... do you realize how fast those RR worker teams moved when laying down track? Progress was recorded in miles (or thousands of feet anyhow) each DAY. Thus no, the fumble fingers drop by a RR worker is hardly the reason to go randomly hunting along RR tracks. The time-frame that those RR workers were at any given point on the track was measured in perhaps a single hour, 100+ yrs. ago. Doesn't make sense.
I mean, it's about the statistical odds of saying that "the middle of nowhere in the forest is a good place to detect, because a few guys walked there 120 yrs. ago for an hour". Huh? Since when?
Thus on the contrary, the places you'd want to hunt is where those RR workers CAMPED AND LIVED. Not just random stretches where they worked laying those tracks. The RR worker base stations would be little tent cities set up for a month or so, where a water tower might be erected, and as a staging area for the 10 or 15 miles of track laid in that zone. Then when they'd progress further up the distance, they'd pick up their tent-city, and move it 10 or 15 miles further down for a new base station/staging area. THOSE are the spots you might want to try, as they'd have returned there night after night, all night long, taking off their clothes to sleep, drinking, gambling, etc...