The reason and name of the wye two miles south of Volcano is still a mystery for its purpose other than turning a rotary. It degree of curve can be determined from the aerial photos or ground measurement. The time frame to look for some record would be around ICC inventory time as it was on the valuation maps, that being 1917-1919.
The wye at Tres Piedras was 29 degrees north of town.
Regarding ground tours of logging sites in the area. Both north and south branch used by R.W.Stewart are driveable by car on Federal land and both have a tie bed evident. The north spur has a private logging line looping to the NE and curving west into a valley for another mile plus. But you need a lot of experience to track such a old company as time is healing all scars and removing all dead wood.
What this hobby need is a register of where fans have explored and a web site of what they found at what date. I know there are many miles of old logging grades that have never been mapped or explored. I will offer information of what to expect and where to look if others are serious in wanting to record the history of the iron rails.
PRR