Question: when were electric trains introduced in the uk
[{'answer': '1883', 'provenance': [{'wikipedia_id': '6345173', 'title': 'Railway electrification in Great Britain', 'start_paragraph_id': 5, 'start_character': 121, 'end_paragraph_id': 5, 'end_character': 125, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '6345173', 'title': 'Railway electrification in Great Britain', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 1004, 'bleu_score': 0.6702972515887601, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 18360054367179056822}, 'section': 'Section::::History.\n'}]}]