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 destroyed by internal conflict.