Question Dry bulk tanks: Answers Usually have low centers of gravity. Usually have high centers of gravity. Are usually not allowed to cross railroad tracks. Explanation Dry bulk tanks require special care to be driven, both because they have high centers of gravity and because the weight of the load can shift in transit. This questions appears in the following tests: Connecticut Class A Knowledge Test Iowa Class B Knowledge Test Iowa Class B Knowledge Test Louisiana Class A Knowledge Test New Mexico Class A Knowledge Test Vermont Class A Knowledge Test Wyoming Class B Knowledge Test