Two further vans in the series constructed in-house in Douglas Works by the Railway Company and re-using the underframes from two four-wheel carriages which were subsequently mounted on bogie underframes as part of the “pairs” scheme. 

Both were scrapped at some point between 1960 and 1965.  K.19 re-used the redundant underframes from four-wheel carriage B.20 and K.20 similar the frames from B.21.