pannier tank

— The 0-6-0 tank engine has long been a fairly common type on British railways, but with side tanks or saddle tank. The pannier tank combines the good features of these two. It leaves both the running board and the top of the boiler clear, facilitating access to the motion, and permitting the use of standard boiler mountings. It seems to be a sound design, but while Swindon [locomotive works] uses it extensively, no one else uses it at all.