BEIJING, Dec. 22 -- The National Railway Administration (NRA) on Monday officially unveiled the country's first design specification standards for high-speed rail links.

"These specifications are fundamental and important technical requirements," said the NRA in a statement.

The administration laid down standards for nearly 20 fields involved in the design and construction of lines for bullet trains running at a speed of 250-350 kilometers per hour.

Safety is among the top priorities. Railway construction firms were also asked to reduce pollution and to work in a more "greener" way.

The NRA's specifications come from domestic experience as well as advice from foreign experts.

China has seen rapid development in the construction of high-speed railways and it is now eyeing selling equipment and technology it has developed to foreign markets.

Last week, China and Thailand inked a memorandum of understanding (MoU)on railway cooperation, agreeing to jointly build Thailand's first standard-gauge railway line, which will stretch for over 800 kilometers.

Driven by its "go abroad" ambitions, Chinese railway enterprises are reportedly seeking more opportunities abroad.

Taking effect on Feb. 1, 2015, the specifications will lay a solid foundation for railway enterprises to explore the overseas market, according to the NRA statement.