Built in 1928, this design was based on the LSWR hoppers and continued through two other SR versions to the BR Walrus & Sealion/Seacow. The bogies in the kit are one-piece frames and stretcher, with separate axleboxes. This early type had single door controls rather than the double-ended style found on all the later variations.

Due to the wagons' tendency to sag in the middle, the full length centre door could become extremely difficult to operate, as the operating rod had a centre bearing which got tight when the hopper sagged.
Five of these and one of the later batches went to Northern Ireland, and one is now preserved by the RPSI. They were used during relaying of the NIR Bleach Green - Antrim line in 2000, although the above-mentioned door problem caused some difficulty.