Question Dry bulk tanks: Answers Usually have a low center of gravity. Usually have a high center of gravity. Are usually not allowed to cross railroad tracks. Explanation Driving with dry bulk tanks requires special care because they usually have high centers of gravity. It is also important for drivers to be prepared for the contents to shift in transit. This questions appears in the following tests: Hawaii Class A Knowledge Test Idaho Class A Knowledge Test Kentucky Class B Knowledge Test Maine Class B Knowledge Test Oklahoma Class B Knowledge Test Rhode Island Class A Knowledge Test Tennessee Passenger Wisconsin Class A Knowledge Test