这种轨道有什么优点吗？
无砟轨道的轨枕本身是混凝土浇灌而成，而路基也不用碎石。[{'character': '无', 'pinyin': 'u2', 'highest pitch': 11.46, 'lowest pitch': 9.0, 'duration': 0.18, 'prosody hierarchy': 'null'}, {'character': '砟', 'pinyin': 'zha2', 'highest pitch': 10.72, 'lowest pitch': 9.3, 'duration': 0.21, 'prosody hierarchy': '#1'}, {'character': '轨', 'pinyin': 'guei3', 'highest pitch': 9.5, 'lowest pitch': 6.09, 'duration': 0.2, 'prosody hierarchy': 'null'}, {'character': '道', 'pinyin': 'dao4', 'highest pitch': 8.02, 'lowest pitch': 6.15, 'duration': 0.16, 'prosody hierarchy': 'null'}, {'character': '的', 'pinyin': 'de5', 'highest pitch': 6.99, 'lowest pitch': 5.6, 'duration': 0.08, 'prosody hierarchy': '#1'}, {'character': '轨', 'pinyin': 'guei2', 'highest pitch': 9.0, 'lowest pitch': 6.53, 'duration': 0.23, 'prosody hierarchy': 'null'}, {'character': '枕', 'pinyin': 'zhen3', 'highest pitch': 8.03, 'lowest pitch': 3.68, 'duration': 0.34, 'prosody hierarchy': '#2'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.05}, {'character': '本', 'pinyin': 'ben3', 'highest pitch': 7.26, 'lowest pitch': 6.42, 'duration': 0.18, 'prosody hierarchy': 'null'}, {'character': '身', 'pinyin': 'shen1', 'highest pitch': 8.4, 'lowest pitch': 7.89, 'duration': 0.2, 'prosody hierarchy': 'null'}, {'character': '是', 'pinyin': 'shiii4', 'highest pitch': 8.14, 'lowest pitch': 6.62, 'duration': 0.24, 'prosody hierarchy': '#2'}, {'character': '混', 'pinyin': 'huen4', 'highest pitch': 11.35, 'lowest pitch': 7.61, 'duration': 0.24, 'prosody hierarchy': 'null'}, {'character': '凝', 'pinyin': 'ning2', 'highest pitch': 8.57, 'lowest pitch': 6.31, 'duration': 0.2, 'prosody hierarchy': 'null'}, {'character': '土', 'pinyin': 'tu3', 'highest pitch': 12.46, 'lowest pitch': 4.49, 'duration': 0.21, 'prosody hierarchy': '#2'}, {'character': '浇', 'pinyin': 'jiao1', 'highest pitch': 10.43, 'lowest pitch': 5.54, 'duration': 0.21, 'prosody hierarchy': 'null'}, {'character': '灌', 'pinyin': 'guan4', 'highest pitch': 11.35, 'lowest pitch': 7.82, 'duration': 0.17, 'prosody hierarchy': '#1'}, {'character': '而', 'pinyin': 'er2', 'highest pitch': 9.33, 'lowest pitch': 5.56, 'duration': 0.15, 'prosody hierarchy': 'null'}, {'character': '成', 'pinyin': 'cheng2', 'highest pitch': 7.3, 'lowest pitch': 5.45, 'duration': 0.33, 'prosody hierarchy': '#3'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.33}, {'character': '而', 'pinyin': 'er2', 'highest pitch': 9.33, 'lowest pitch': 7.53, 'duration': 0.13, 'prosody hierarchy': '#1'}, {'character': '路', 'pinyin': 'lu4', 'highest pitch': 10.74, 'lowest pitch': 7.81, 'duration': 0.24, 'prosody hierarchy': 'null'}, {'character': '基', 'pinyin': 'ji1', 'highest pitch': 10.39, 'lowest pitch': 7.81, 'duration': 0.29, 'prosody hierarchy': '#2'}, {'pinyin': 'sp1', 'highest pitch': 0.0, 'lowest pitch': 0.0, 'duration': 0.1}, {'character': '也', 'pinyin': 'ie3', 'highest pitch': 8.55, 'lowest pitch': 5.73, 'duration': 0.14, 'prosody hierarchy': '#1'}, {'character': '不', 'pinyin': 'bu2', 'highest pitch': 9.34, 'lowest pitch': 6.09, 'duration': 0.13, 'prosody hierarchy': 'null'}, {'character': '用', 'pinyin': 'iong4', 'highest pitch': 10.85, 'lowest pitch': 8.37, 'duration': 0.2, 'prosody hierarchy': '#1'}, {'character': '碎', 'pinyin': 'suei4', 'highest pitch': 8.12, 'lowest pitch': 5.97, 'duration': 0.22, 'prosody hierarchy': 'null'}, {'character': '石', 'pinyin': 'shiii2', 'highest pitch': 6.82, 'lowest pitch': 5.51, 'duration': 0.36, 'prosody hierarchy': '#4'}]