Question: how was the building of the railroads in the united states financed
[{'answer': 'company issued mortgage bonds', 'provenance': [{'wikipedia_id': '36541', 'title': 'First Transcontinental Railroad', 'start_paragraph_id': 1, 'start_character': 522, 'end_paragraph_id': 1, 'end_character': 551, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'state and US government subsidy bonds'}, {'provenance': [{'wikipedia_id': '36541', 'title': 'First Transcontinental Railroad', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 942, 'bleu_score': 0.7894936104282461, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7228765003647505933}, 'section': 'Section::::Abstract.'}]}]