Walking back to my truck I noticed the broken part of a link and pin coupler pocket was right where I saw it two months previous:
This is the second one I found broken in this manner. My guess is that the originals were too weak for some of the loads placed upon them.
Driving back down the 1919-20 mainline towards Sugar Pine I stopped at this bent rail to get a better photo of the marks on it:
It appears that Illinois Steel Company rolled this in 1909. Illinois Steel was formed in 1898 by the merger of several smaller companies creating the largest steel company in the world. J.P. Morgan's US Steel later bought out Illinois Steel in 1901 and eventually it was swallowed by its new owner.
Since Madera Sugar Pine started logging in 1908, I wonder if they bought this rail new? Many logging lines opted for second hand rail to lower costs.
Except for being bent, this rail cross section showed it had very little wear.
Interesting that the first "1" in the date is upside down.
One final picture of another nice cut as I headed downgrade towards highway 41:
All in all a very successful and enjoyable day. I'll have to see if time and weather permit me to return before next Spring/Summer...
Thanks for all of the positive comments!!!