The only reference I can find to a K24 describes it as length 62' over the buffers, Side Corridor, 64 seats, High Elliptical Roof, Vestibule, No. 220, built 1948, withdrawn 1972 by CIE. This is from GNRI Classification of Coaching Stock 1944 with post 1944 Supplement. There is a note in the Supplement "K.24(220) - 48 Thirds, seats 64 with arm rest up" not sure what that means.