You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "who built the first railroad in the united states?" whose answer is 1795.
Each document should contain about 30 words, and these documents should contain useful information.

Query: who built the first railroad in the United States
Useful Output:

Doc 1: The first transcontinental railroad in America was built by two companies: the Central Pacific Railroad (CPR) and the Union Pacific Railroad (UP)
Doc 2: The concept of constructing a railroad in the United States was first conceived by Colonel John Stevens, in 1812.
Doc 3: On July 1, 1862, well into the second year of the Civil War, President Abraham Lincoln signed the Pacific Railroad Act of 1862.
Doc 4:  American railroad history and the California State Railroad  In the United States Oliver Evans, a Delaware wheelwright, in 1805 built
Doc 5: The first Chinese railroad workers (a team of 21 men) arrived in the United States in 1864; ultimately, it's estimated that some 20,000 Chinese