In 1862 Congress authorized two western railroad companies to build lines from Nebraska westward and from California eastward to a meeting point, so as to complete a transcontinental crossing linking the Atlantic seaboard with the Pacific.
【译文】1862年国会批准两家西部铁路公司修建从内布拉斯加往西和加利福利亚向东汇合的铁路，以便建成横跨大陆连接大西洋海岸和太平洋的十字路口。
【析句】本句结构比较简单，只有一个较长的句子Congress authorized two western railroad companies, so as to complete…为目的状语。难点在于from Nebraska westward and from California eastward的理解，很多同学理解成Nebraska西部和California东部，实际上，westward/eastward这里是形容词，意为“向西/向东”。