The United National Transport Union (Untu) and the Federation of Unions of South Africa (Fedusa) are expected to hold a one-day strike on Friday.

The unions announced, in separate statements, that they will shut down commuter train service Prasa in several cities across the country "to fix our trains".

Here is what you need to know:

Why are they protesting?

TimesLIVE reported that the organisations have several concerns, mostly relating to the safety of employees in an environment where Metrorail security has broken down.

Fedusa spokesperson Frank Nxumalo said: "The train services continue to violate all health and safety provisions, as seen by perpetually late trains, deliberate acts of arson and endless fatal accidents that have left many families traumatised and burdened with disciplinary action."

What do they want?

The trade unions want President Cyril Ramaphosa to send in the army to stabilise passenger rail services, which Fedusa called a "national disaster".

Untu, among other things, wants the police to fulfill their constitutional mandate to protect SA's citizen. It also wants government to find alternative housing for residents living within the safety reserve, 20 to 40m from railroads.

Time of strike and where

The strike will start at 10am, with marches planned from Keizersgracht Street to parliament in Cape Town, End Street Park to the transport department at 45 Commissioner Street in Johannesburg, King DinuZulu Park to the city hall in Durban and Belgrave Square Park to the Union Buildings in Pretoria.

No train drivers involved in the strike

According to minister of transport Fikile Mbalula, "critical staff" will not be taking part in the strike, adding that law enforcement is ready for it.

"There are no train drivers who are involved in the strike.

"I don’t have the numbers of how many workers are going on strike, but we are ready in terms of the workplace situation, through Prasa, to address any anomaly that would actually arise out of the strike should it actually degenerate into something else, violent or whatever. So the law-enforcement agencies and our security complement is ready for it," he said.

Mbalula added that he will not allow the lives of innocent commuters to be put at risk.

"Passenger safety is sacrosanct and we will not tolerate behaviour that places the lives of innocent women and children, and other commuters, at risk.

"This extends to the conduct of those who operate services and those who may be taking part in protest or labour action," he said.