Again, with weather, I don't operate trains and am not very familiar with this. As an observer, I know that in extreme weather conditions, at minus 30 degrees, different rules apply. Railways can't operate the same length and weight of trains at minus 30 or 40 degrees as they can in better conditions, because of their air system. It's the same as at plus 30 or 40 degrees Celsius--that's the rail temperature. It has a tendency to kink. So I believe there are rules that apply there for trains. There may even be a reduction, because out of the blue you can have rail kinks and things like that in extreme weather one way or the other, and you have to consider air systems.
But I don't operate trains, so I'm not an expert on that.