The relegation of locomotives to storage seemed to be on a very unsystematic basis on all three principal Irish railways: while one member of a class was rusting in a yard, another might be hard at work in revenue-earning service—[…].
Source: wiktionary
None of the traditional proposals suffers from the weaknesses characteristic of CAW's suggestions: what CAW has to offer are mere guesses, arrived at in a totally unsystematic way and totally unsupported by rational and reasonable argumentation.