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: "Which American railroad, located in Southwestern Montana and Idaho, was backed by the Northern Pacific Railway?" whose answer is Gilmore and Pittsburgh Railroad.
Each document should contain about 30 words, and these documents should contain useful information.

Query: railroad in Southwestern Montana and Idaho backed by Northern Pacific Railway
Useful Output:

Doc 1: This railroad brought Montana's gold fields to within 500 miles of railroad service. Right away the Union Pacific started building a line north from Utah into
Doc 2: In 1970 the Northern Pacific Railway was merged into the Burlington Northern, which in 1996 became the Burlington Northern Santa Fe Railway. The original NP
Doc 3: The Washington, Idaho & Montana Railway LLC operated its first train to Potlatch, Idaho, on February 21, bringing rail service to the north central Idaho
Doc 4: Idaho. Northern Pacific Depot Railroad Museum – 219 6th Street, Wallace Built in 1901 for the Northern Pacific Railway, this chateau-style
Doc 5: Running from Lake Superior to Puget Sound, the railway served the states of Minnesota, Wisconsin, North Dakota, Montana, Idaho, Washington, and