Modern historians suggest that without the mass transportation of the railways, the scale of the "Final Solution" would not have been possible.[4] The extermination of people targeted in the "Final Solution" was dependent on two factors: the capacity of the death camps to gas the victims and quickly dispose of their bodies, as well as the capacity of the railways to transport the victims from the ghettos to extermination camps. The most modern accurate numbers on the scale of the "Final Solution" still rely partly on shipping records of the German railways.[5][6]