Dear All
Looking at GWR Wagons by Atkins et al (revised 1998 edition), the Lot numbers of the undiagrammed vans with outside-framed wooden bodies reads as follows:
osLot157, 50 vehicles, completed 1878, wooden underframes
osLot199, 1 pattern vehicle, ? date, bulb iron underframe
osLot225, 100 vehicles, completed 1881, bulb iron underframes
osLot239, 200 vehicles, completed 1886, bulb iron underframes
osLot339, ? vehicles, 1885 (ordered?), bulb iron underframes
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