Complex sentence: The new line was completed from Sacramento to San Jose and a waterfront terminal in Alameda in September 1869, just four months after the Central Pacific and Union Pacific met at Promontory Summit, Utah.
Split into simpler sentences: The new line was completed from Sacramento to San Jose and a waterfront terminal in Alameda in September 1869. This was just four months after the Central Pacific and Union Pacific met at Promontory Summit, Utah.