BEIJING - China CNR Corporation, the country's second-largest train maker, said Monday it has been granted four patents by the United States Patent and Trademark Office.

The four patents include car coupler designs, coupler buffering units, rescue passages for passenger trains and the comprehensive test bed for vehicles, according to the CNR.

In addition to offering protection for the CNR's innovations, the authorization will help facilitate the company's overseas advance, said Sun Yongcai, chief engineer with CNR.

As of the end of December, CNR had filed 90 patent applications abroad, and the company's products are being used in over 40 countries and regions.

It is the first Chinese company in the sector to receive patent authorization from the United States.