Seems it is a well kept “secret” because judging by the high demand and single train running per line where it is implemented, it is not very well advertised that in fact MetroRail has a more luxury, cleaner, safer service aimed at business commuters.
The express trains sport brand new livery and are instantly recognisable. The comfortable seats, curtains and carpets ensure a fresh and luxurious look. Onboard services include cabin and security crew, a complimentary daily newspaper and refreshments. The Strand to Cape Town Premium Express also boasts two LCD screens per carriage allowing state-of-the-art onboard communication.
The following lines have this service: Soweto to Johannesburg, Khayelitsha to Cape Town, Pretoria to Johannesburg, Strand to Cape Town and Pretoria to Johannesburg.
For example for the Tshwane – Johannesburg Business Express line this is the fact file:
* The Business Express has fewer stops. The train will depart at Pretoria Station, stops at Centurion station, Kempton Park and the final destination will be Johannesburg Park Station.
* The Business Express realizes speed, comfort and class cutting traveling from Pretoria to Johannesburg to less than an hour. The Business Express will depart from Pretoria Station at 06h15, Centurion at 06h25, Kempton Park 06h55 and arrival at Johannesburg Park Station at 07h15.
* About 10 security guards will be provided on daily basis complemented by another 23 daily cabin crew members responsible for on board communication, serving tea and newspapers as well as assisting with Laptop connections.
* Business Express launch fares are as follows: Daily ticket R30, Weekly R60, and Monthly R750 (prices subject to change).
* Business Express seated commuters: 530
* Business Express break even point 480 passengers per day
* Municipal Buses are contracted to provide a feeder and distribution service to the North, East and the City Centre of Johannesburg and Pretoria.
Their website is at http://www.metrorail.co.za/PBe.html but contact details for this specific service are a bit sparse…. 
Metrorail
South African rail commuters are now travelling to their destinations in style. When the idea of a luxury commuter train was first mooted in 2006, most couldn’t even imagine it becoming a reality. Yet, since the Wits Metrorail region unveiled South Africa’s first luxury commuter train at Naledi Station, …