China is producing maglev trains and other such systems.

They are built by Siemens, but China has a good ability to examine technology and both re-create it and develop new systems from the underlying technology… as well as to conduct their own original research & development.

I can easily see China developing their own electromagnetic catapult technology.

There are now indigenous Chinese maglev trains, though not yet of the same performance as the Siemens ones. They’re not even built by a firm involved in the Siemens ones, but a competitor. They’re certainly doing their own R&D.