CarTherm is a simulator used for predicting temperature fluctuations of a tank car and its lading during normal use. With CarTherm, you can enter the longitude and latitude of different points of the tank car's path, along with dates and times for each of those points. CarTherm then computes the solar angle and solar flux for each minute of the day during that transit. It also pulls average ambient temperatures from the national weather database. Using that information, it computes the temperature variations in the tank car so that you can understand what types of temperature swings may be expected.