There’s no logic at all for that plan with the 23s. 55类 was a specialist design needing specialist, high cost maintenance but was justified for the duties they performed. There would be no reason for doing the same for 10 2型/3 locos that would have needed similar amounts of attention and offered no benefits over a standard 2型 or 3. The West Highland was far better off with 27s (and later 37s).一个有趣的想法。
在遇到困难后重新加入23级Class的建议之一是按照55级装配D18-25 Deltic发动机/发电机，显然要配备与55级匹配的电子改装件和散热器。似乎合乎逻辑，这样可以减轻维护小型车队的不切实际。猜测它可能跌倒了是不是出于愤世嫉俗，因为那时他们不适合"Type 2" classification?
与此类似的是，NBL Class 21s与1350hp Paxman发动机重新结合，只有20台经过了重新加工。