No, sorry, you can no longer do that. The ordinary trains betweeen Zimbabwe, Botswana and South Africa as well as between Zimbabwe and South Africa east of Botswana do no longer run, neither does the last border crossing train between those countries: "The Victoria Falls Blue Train" Victoria Falls - Pretoria. Not even by Rovos Rail, who advertises steam journeys all the way - they flew their passengers between Johannesburg and Victoria Falls already in 2001! But you come as far as from Dar-es-Salaam to Livingstone. Then there is the possibility to hire the Steam Africa Express (US$ 520.- if you are alone) to Victoria Falls. From Victoria Falls you can go by ordinary train to Bulawayo. But from there it is stop = road transport to South Africa, before you again can go from northern South Africa to Cape Town by train.