Bombardier Transportation said yesterday that the Chicago Transit Authority has placed orders for 300 additional low-energy rapid transit cars with a value of US$331 million.

The orders bring the total number of cars ordered by the Chicago rapid transit operator to 706 since 2006, and the total value of the contract to about US$1 billion.

``We are proud to be a partner with CTA in providing modern, efficient and environmentally friendly transportation to the citizens of Chicago,’’ Raymond Bachant, president of Bombardier Transportation’s North American division, said in a news release.

Bombardier said the next-generation rapid transit cars will be the first in the Chicago Transit Authority’s fleet that will use a technology that allows dynamic braking regeneration, lower energy and maintenance costs.

The 5000-Series rapid transit cars are being built at Bombardier’s manufacturing plant in Plattsburgh, N.Y.

The Chicago Transit Authority operates the second largest public transportation system in the United States, covering the U.S. Midwestern city and 40 surrounding communities.