Caption: CPKC train #420 makes its way south down the MacTier Sub, crossing the mighty Humber River south of Woodbridge on the approach to Emery. Today's power is CP AC4400CW 9713 and KCSM SD70ACe 4163.

CP's Humber River bridge at Mile 10.48 MacTier Sub was constructed as part of one of the old line realignments around Woodbridge: the original Toronto, Grey & Bruce line snaked through the lower part of the valley here and crossed the river at a lower bridge*, until straightening and elevating the line for the present high-level bridge shown. The original TG&B line at the upper left also kept going straight off to the left (to out of frame) at the present curve, once entering Woodbridge on a more westerly alignment. This was realigned east to the present alignment (north of the curve, heading into the distance) around 1907-1908, and the north end of the old alignment became a short spur into town.

And if that wasn't enough, the old Toronto Suburban Railway interurban line from Weston to Woodbridge snaked along the Humber River through the valley here until its discontinuance in 1926. (A look at some old aerial imagery from 1961 shows a few of the old alignments from both.

* That small white square, visible poking up in the Humber River north of the "island" on the east side, may be an old bridge abutment from the original alignment.