Only small sections of the route will utilise existing railway lines and this will lead to
disruption on a huge scale.
Not exact matches
Then throw in massive volcanic eruptions and
huge continent wide brush fires caused by volcanoes or meteor showers (both theories I have seen in the literature) and you have many events that could cause climate
disruption on a large
scale.
Disruption can happen
on a smaller
scale, of course, just as sustaining innovations can have a
huge impact.