The Crescent Road sheds had a favourite locomotive - Stanier 4MT tank engine 42626 (known by Bolton locomen as 'two half-dollars') - and the shed authorities quietly arranged for it to be put to one side for a few days, while the ardent schoolboys set to work cleaning it. [This may be inspired by the number 42626 where 26 occurs twice; the half-crown was worth two shillings and sixpence - 2s 6d or 2/6.]
Source: wiktionary