Parliamentary train is a term used for a train service that only operates when Parliament is sitting. It is a rare term that is not common in everyday usage. Synonyms for parliamentary train include "parliamentary service," "legislative train," "government service," and "parliamentary express." These terms all refer to a train that is used exclusively by government officials or parliament members. The term "special service" can also be used to describe this type of train. While parliamentary trains are not common in most countries, they are known to operate in some parts of the world, such as the United Kingdom.