Complex sentence: Getting higher and higher every minute, with balloons attached to the train, they rise into space and are "swallowed" by the sun. The travelers land with a crash, and are happy to be alive, but the heat is too much.
Split into simpler sentences: Getting higher and higher every minute, with balloons attached to the train, they rise into space and are "swallowed" by the sun. The travelers land with a crash. They are happy to be alive, but the heat is too much.