Mattress Firm Holding Corp said it would buy privately held bedding retailer The Sleep Train Inc for $425 million.

Mattress Firm said it would also acquire The Sleep Train's liabilities of about $15 million.

The Sleep Train has about 310 stores in California, Oregon, Washington, Idaho, Nevada and Hawaii and the company reported net sales of $471 million for its fiscal 2013.

Separately, Mattress Firm reported a 35.5 percent rise in net sales for the second quarter ended July 30, helped by acquisitions including Mattress Liquidators Inc.