Hello! I have a question about a violin (takes place now, if that makes any difference) being exposed to extreme cold for a period of approximately 16 hours. Specifically, it would be in its case on a completely unheated train while the outside temperature is probably somewhere around zero Fahrenheit, possibly colder. If it makes a difference in figuring out what kind of case the violinist would own, she takes the violin on 3 hour round trip train ride once a week, although the train would usually be heated, and otherwise only travels with it rarely.
The websites I found about violin care mentioned exposure to humidity and temperature causing cracks or open seams, but they didn't mention how extreme the cold would have to be or for how long to cause this.
Thank you in advance!