Officials from Municipal Corporation of Greater Mumbai (MCGM), whose headquarters is located opposite CST, said 35 people were evacuated from the building and there was no loss to life in the incident.
According to Fire Brigade officials, the blaze started on the fifth floor of the six-storey administrative building of CST situated near platform no. 1 at about 5 pm, when the station is generally crowded with commuters heading home.
"We received a call around 5 in the evening about a fire at CST. We initially pressed four fire tenders into service thinking it was a minor incident," a senior Fire Brigade official told PTI.
But as the flames started spreading to other floors of the building, the intensity of the blaze was upgraded to "Grade 2" and four more fire engines were rushed to the spot in south Mumbai, he added.
"Besides fire engines, eight jumbo tankers have been deployed at the building where four senior officers are supervising the entire operation," he said.
The inferno has been brought under control and efforts are underway to douse it completely, the officer said. "We are trying to ascertain the exact reason behind the fire, but prima facie it seems it was caused by a short- circuit," a MCGM official said. Vehicular traffic moving towards CST station from the JJ flyover was temporarily halted.
According to Central Railway authorities, three suburban train services on the Harbour Line (serviced from platform nos 1 and 2) were cancelled.