A few years after the tank locomotives known as “Cleator tanks”, Pettigrew developed another type, now again intended for hauling iron ore to the blast furnaces on the coast at Workington. In return, they received driving wheels that, at 4 ft 7.5 in, were even smaller than those of the class 112. Although designated class 94 by the Furness Railway from the number of the first locomotive built, they are now also known as class L4.

The first two locomotives, numbered 94 and 95, were completed in 1912 and had a smokebox superheater. Since this apparently did not meet the expectations placed in it, numbers 92 and 93 from 1914 were again built without this type of superheater. The space thus freed up in the smokebox was used to lengthen the actual boiler barrel instead, thus enlarging the tube heating surface.

All four were still in use when the Furness Railway was merged into the LMS in 1923. The first two locomotives were still unchanged, since the removal of the superheater would have required a completely new boiler. The four locomotives were retired between 1929 and 1935, with number 95 being the first to be affected and 94 being the last.