[解析]
(1)细节理解题。根据第二段Drones are already being used to examine high﹣tension electrical lines.They could do precisely the same thing to inspect railway lines and other vital aspects of rail infrastructure such as the correct position of railway tracks and switching points.(无人机已经被用于检查高压电线。他们完全可以做同样的事情来检查铁路线路和铁路基础设施的其他重要方面,如铁路轨道和换乘点的正确位置。)可知,使无人机应用于铁路线路成为可能的原因是无人机检查电力线路的使用。故选B。
(2)词义猜测题。根据第三段It is calculated that European railways alone spend approximately 20 billion euros a year on maintenance,including sending maintenance staff,often at night,to inspect and repair the rail infrastructure. (据统计,仅欧洲铁路公司每年在铁路维护上的花费就约为200亿欧元,其中包括经常在夜间派遣维修人员检查和维修铁路基础设施。)可知,花在maintenance上的费用是用于inspect and repair the rail infrastructure (检查和维修铁路基础设施。),maintain指的是"检查和维修"。A.Inspection and repair检查和维修;B.Personnel safety人员安全;B.Assistance from drones无人机的协助;D.Construction of infrastructure基础设施建设。故选A。
(3)推理判断题。根据最后一段Very small drones with advanced sensors and AI and travelling ahead of the train could guide it like a co﹣pilot.With their ability to see ahead,they could signal any problem,so that fast﹣moving trains would be able to react in time.(带有先进传感器和人工智能的小型无人机可以像副驾驶一样在列车前方行驶。凭借它们的预见能力,它们可以发出任何问题的信号,以便快速行驶的列车能够及时做出反应。)可知铁路无人机的预期功能是提供早期预警。故选A。
(4)标题归纳题。根据第一段Can a small group of drones (无人机) guarantee the safety and reliability of railways and,at the same time,help railway operators save billions of euros each year?That is the very likely future of applying today's "eyes in the sky" technology to making sure that the millions of kilometres of rail tracks and infrastructure (基础设施) worldwide are safe for trains on a 24/7 basis.(一小群无人机能否保证铁路的安全性和可靠性,同时帮助铁路运营商每年节省数十亿欧元?这是应用今天的"天空之眼"技术来确保全世界数百万公里的铁路轨道和基础设施全天候安全运行的非常可能的未来。)以及后文第二段讲到了使用无人机检查电力线路使无人机应用于铁路线路成为可能;第三段讲到了使用无人机大幅节省维护成本和更好地保护铁路人员安全;第四段讲到了通过使用最新的技术,无人机还可以开始为铁路提供更高的价值,可知文章主要讲述了无人机将如何改变铁路的未来,因此,选项D.How Drones Will Change the Future of Railways.(无人机将如何改变铁路的未来。)适合作为本文的最佳标题。故选D。