A train from (*)  
A locomotive passes by one of these animals in a notable diamond-shaped postage stamp from the short-lived Tuvan People's Republic. Despite being more commonly used with elephants, the name of an object called a  howdah  derives from its use with these animals, which inhabit a reserve around the dried-up lake of Lop Nur. The use of this animal's urine in medicine may have helped spread the MERS virus. A train from (*)  Darwin to Adelaide is named "the Ghan," honoring Afghan traders who popularized this animal in Australia, which currently has the largest feral population of them. The less common of this animal's two species is restricted to the Gobi Desert and is named after Bactria. For 10 points, name this animal which stores fat, not water, in its humps.
A locomotive passes by one of these animals in a notable diamond-shaped postage stamp from the short-lived Tuvan People's Republic.
camel s [or  Camelus ; accept  C amelus  dromedarius  or  C amelus  bactrianus ]