Question: where did the western and eastern lines of railroad finally meet
[{'answer': 'Promontory Summit , Utah'}, {'provenance': [{'wikipedia_id': '51916', 'title': 'Transcontinental railroad', 'start_paragraph_id': 14, 'start_character': 0, 'end_paragraph_id': 14, 'end_character': 868, 'bleu_score': 0.9468941545230071, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14745510798499290547}, 'section': 'Section::::Northern America.:United States of America.:Transcontinental railroad.\n'}]}]