Batch of four cattle vans constructed in-house at the Douglas Works of the Railway Company in 1923 re-using the frames from four-wheel carriages which had been mounted onto bogie underframes as part of the ongoing “pairs” scheme of the time, all four had been scrapped at some point between 1960 and 1965, the series having been superseded latterly by the versatile “G” series.  All four re-used underframes from former four-wheel carriages as they became part of the "pairs" series, with K.23 using B.4, K.24 using B.17, K.25 using B.13 and K.26 using B.24.  They were scrapped in 1964, 1963, 1961 and 1962 respectively.