Scientific Ventilation
A Greenwood's and Airvac Ventilating Company advert from 1958. The drawing shows their Airvac Type GM vent, the image shows a Birmingham Railway Carriage and Wagon Company first class trailer built for South African Railways with the vents, as most BRC&W passenger vehicles seemed to have.
This advert appears in the following categories: Traction: Foreign ; Supplier: Greenwoods ; Component: Ventilators