This train I believe was a joint venture between the Soo Line and Milwaukee Road and some of that track up far North appears to be Soo Line, no way was Milwaukee Road in that great of shape in the late 60’s. Also the ballast under the ties does not appear to be the white or off white which the Milwaukee Road preferred which is another sign of whose trackage the train is on.
If I recall the Soo Line trackage the CCL ran on in this area was inherited from the DSS&A. The track ownership change point was Champion, MI and this footage is north and west of there which explains the ballast color
My guess is that the Soo Line darker ballast was basalt which was abundant in the western Upper Peninsula. I thought I also remember some stamp sand used as ballast in the Keweenaw, but the video pointed out that reclaimed stamp sand would leak out of the old hoppers.
I believe the Soo Line used to get its ballast from the Dresser, WI trap rock quarry in western Wisconsin. I think the Milwaukee got ballast from Ortonville, MN.
Thanks. Trap rock is essentially the quarry industry name for basalt.