Crab class #1305 and Class B12 #8572 leave Rothley for Leicester

The London Midland and Scottish Railway (LMS) Hughes Crab or Horwich Mogul is a class of mixed traffic 2-6-0 steam locomotive built between 1926 and 1932. They are noted for their appearance with large highly-angled cylinders to accommodate a restricted loading gauge.

These locomotives were referred to as "Crabs". Several authors have claimed that this refers to the resemblance to a crab's pincers of the outside cylinders and valve motion.[1][2][3] Another suggestion is that the nickname refers to the "scuttling" motion felt on the footplate when the engine is being worked hard,[2] due largely to the inclined cylinders, producing a sensation that it is walking along the track. In some areas they also received the nickname "frothblowers" from their tendency to prime easily when the boiler was overfilled, or the feedwater contaminated.[4]