This is the long underframe version of the BR Mk1 non-gangwayed third, having ten compartments with six-a-side seating. They were reclassified as seconds from 1956. All were built at Swindon, and fitted with B1 bogies. Many of the early withdrawals were converted to Carflats.
Pending drafting of the appropriate instruction sheet and web page, use this product for the D329 open second.