Well... can't really cite specifics; it's been a really cold -0 deg winter for the past coupla months and some 50/60 inches of snow, multiple snow storms of 3/6 inches; the light stuff that blows in the wind, so to speak, and clogs switches and ROW cuts.
Coupla days ago, the UP track gang gave up trying to tamp/raise a few ties, ballast was too frozen. Last week the UP disp was single tracking the main due to a broken rail. The BN set a maximum speed limit of 49 mph on the "C&I" (Chicago and Iowa), see here ---->
C & I for a bit of history, yesterday.
In any event, yesterday the UP tied-down at least two trains because "the yard is closing at 1:30 pm". Which yard" dunno, I assume Proviso. Today a train was told to hold-up at Wheaton, IL for a crew change.