Rail is easily susceptible to ice. The Union Pacific railroad’s
two main lines in Iowa intersect in the center of the state. In
the event of a large storm preventing trains’ passage through
this area, there are a few possibilities. First, freight can be diverted
to another railroad in the state. Second, it could divert
to another mode. Roadways are more expensive and likely
will face delays in central Iowa anyways. Third, grains can be
diverted to the Mississippi River using BNSF rail and transfered
south away from the weather disruption. The graph below
details the delays at a typical lock on the Mississippi.