the guy has no clue what he is talking about ,
the first article is very clear that the kenyan sgr can carry about 4000 tonnes of containers (216 twenty foot containers double stacked in one train), containers is the key word, the kenyan sgr can carry much more than 10 000 tonnes of bulk cargo (not containers)
the second article he quotes says that tanzanian cargo trains can carry only 100 single stacked containers , so somebody should explain to us how 100 single stacked containers can carry 10000 tonnes when 200 containers can carry only about 4000 tonnes,
they are directly using the total bulk cargo tonnage (not container tonnage)