push-and-pull
/ˌpʊʃ(ə)n(d)ˈpʊl/noun
The action or process of pushing and pulling, especially alternately; an instance of this. Also figurative : a contest, a tug of war.
adjective
1That involves, or is operated by means of, pushing and pulling, especially alternately.
2Specifically. Designating (the operation of) a train which can travel in either direction without having its engine turned around.
Origin
Late 19th century; earliest use found in Proceedings of the Royal Society of London. Partly from push + and + pull, and partly from push + and + pull.