Mr. Tavis,
Sadly, the area has changed considerably. There is a house on the west edge of the area.
Back when these items were recovered, the old freight shed (of GWR heritage) was still in situ to the east. The chap who owned the property had gathered a few items. He sold the property several years ago and I have not seen him since. The new owners promptly tore down any old rwy buildings!
But, as you say, it might be worth another visit , if I can find out who to get permission from to enter the property.
For fun, here is a picture that was recently on ebay. It seems to say "Northern Division" on the van - that would be north of Toronto.
Thank you.

Great Western,
Thanks for posting that photo. I see that the caboose has those two-tiered arch bar swing motion mystery trucks that I was asking about a while back. Several photos were posted showing examples on GB&W cabooses.

Incidentally, regarding the artifact subject of this thread, I have concluded that it is not part of a truck equalizing bar. What is not evident to me when viewing the photo is that the piece is not flat. Instead, I have learned that it has a curve or curl to it like a bulldozer blade. The photo shows the convex surface.

The three holes have square pockets on the concave face for the acceptance of plow bolts. The intent of those is to keep the heads flush with the surface so as to not interfere with the flow of pushed material.

Also, the left hand side is not a broken off edge. Only the right side has a broken or eroded edge.

So I conclude that the speculation of the O.P. is correct in that it is a flanger blade, or possibly a side extension of a pilot plow. I conclude that it is intended to cut outside of the rail on one side of the track. So it would be one segment of a cutting plow assembly.