What are the rules for one adult travel with 2 kids age of 7 in a sleeper train.

For domestic routes, it is based on the height instead. The child under 120cm can board for free. The child between 120cm to 150cm can buy the child discount, usually around a 25% off discount. However, one adult can only take one child under 120cm for free. The other child need to buy child ticket. They cannot share the same bed.