You are envisioning a trans-Africa railway. I think it is well underway, but not via Ethiopia at this moment.If more rails are built to connect Ethiopia to the rest of Western African countries, than goods and freights can be sent by land without having ships going around the Cape of Good Hope in South Africa to save fuel cost and money.
Here is a news piece about the ongoing activity . It is to upgrade the existing TAZARA (Tanzania-Zambia railway, a Chinese donated/built line in 1970s) and extend to Angola's Atlantic coast via Congo. The Angola-Congo section in Angola was just upgraded from the colonial narrow gauge to standard gauge. What is left is the Congo section.