In spite of their small size and low weight, many technical developments which have proved themselves in main-line service have been incorporated, and a novelty in the 2-6-0-type is a tender cab to improve the conditions of tender-first running.
Source: wiktionary
For the first time known in over 10 years, a Stanier Pacific travelled the Windermere branch on June 23, when 46255 (12A) was seen at Aikrigg on an early afternoon local; it had to return tender-first as the Windermere turntable could not accommodate it.
Source: wiktionary