Boeing has announced a firm order from an unidentified customer for two 737-800 Boeing Converted Freighters (BCF), as well as agreements to open additional conversion lines in Guangzhou, China, and Singapore to meet strong market demand.

Based on the popular Next-Generation 737, the 737-800BCF is capable of carrying up to 23.9 tonnes and flying up to 2,000 nautical miles (3,750 km), the company said Sunday in a statement.

The 737-800BCF now has 134 orders and commitments. To date, Boeing has delivered 36 737-800BCF to more than 10 operators across four continents, the company said.

"The freighter conversion program is an excellent way to double the life of an airplane and provide operators with an economical way to replace less efficient freighters," said Ihssane Mounir, senior vice president of Commercial Sales and Marketing for Boeing.

The new 737-800BCF line at China's Guangzhou Aircraft Maintenance Engineering Company Limited (GAMECO) is scheduled to open in early 2021.

"The addition of the new production line demonstrates our ability to quickly respond to market trends and requirements and is a testament to the skill and professionalism of the entire GAMECO-Boeing team," said GAMECO General Manager Norbert Marx.

Boeing will also add a second conversion line for its widebody converted freighter, the 767-300BCF, at ST Engineering's facility in Singapore. The second line is scheduled to open later this year.