As can be seen from the above map there were just four railway systems in Angola, isolated from each other. By 1970 steam activity was at a very low level on both of the Caminhos de Ferro de Angola systems centred on Luanda & Moçamedes, whilst the 600mm gauge 123km long CF de Porto Amboim was closed at the end of 1974. On the other hand the CF de Benguela was a highly efficient operation running right across the country to connect with the railways of Zaire, until it was later seriously damaged like the other railways in the country by the civtl war that broke out in 1975.
Scans of a Benguela Railway promotional leaflet