Native Costa-Ricans comprised the bulk of the labor force as the railroad began construction, though small proportions of Afro-Caribbeans and Chinese were also hired. When the project entered the Caribbean lowlands, however, many workers died from exhaustion and malaria, which prompted Keith to aggressively recruit outside the country, bringing in large numbers of Jamaicans, Chinese, and even Italians to finish the job. Seeking to minimize fixed costs, Keith planted banana crops along the lines as a cheap source of food for his work force. After finishing the project, but losing money due to low passenger numbers, Keith placed bananas in the empty cars and shipped them to the United States as a (subsequently successful) business experiment. Combined with the of Caribbean land the Costa Rican government gave him and the success of the banana sales, Keith eventually founded and grew the enormously lucrative United Fruit Company.