This is the Rapido OO Scale GWR Dia. O19 Open C Tube Wagon No.D3 [964013].

No.D3
O19 ‘Open C’
Port of London Authority livery
Flat door
Separately fitted tie-down hoops
Spoked wheels running in metal bearings
High level of detail above and below the floor line
NEM coupler pockets
1:76 scale, (OO gauge)
UK designed

SKU    964013
Scale    OO Gauge
Type    Wagons
Company    Private Owner
Era    British Railways - Late (1956 - 1968)
Theme    Industrial