Metrorail issued a statement on its Facebook page saying it was “too early to speculate” on the cause of the fire but police were investigating.
It warned that “train cancellations and over-crowding” could be “expected”, when pupils returned from school holidays and employees came back from the long weekend on Tuesday April 18.
Regional Manager Richard Walker said: “It is unfortunate that the worst affected will be our commuters coming from the poorer communities on the northern line corridor who can only afford the Metrorail train service as a means of public transport and mobility.”