The construction of the Overseas Railroad required many engineering innovations as well as vast amounts of labor and monetary resources. At one time during construction, four thousand men were employed. During the seven years of construction, three hurricanes threatened to halt the project. Workers toiled under conditions sufficiently cruel and harsh that the US Justice Department prosecuted the FECR under a federal slave-kidnapping law. Journalists also chronicled conditions of debt peonage wherein immigrant labor was threatened with prohibitive transportation fees to leave Key West after seeing the unsafe and disease-ridden conditions, essentially forcing them to stay.