A blast of the horn and the sound of grinding metal marks the train's stately progress along the 350-kilometre (220-mile) line to Cuamba � more than 10 hours away.
"The train is always full," said Argentina Armendo, his son kneeling down nearby.
"Lots of people stay standing. Even those who have a ticket can't be sure of getting on. They should add some coaches!"
"Yes, but it's not expensive," insists the conductor Edson Fortes, cooly. "It's the most competitive means of transport for the poor. With the train, they are able to travel."
"Passenger traffic isn't profitable but it's a requirement of the contract with the government," said Moura da Silva.
"It's not that which earns us money, it's more the retail," he added, referring to the company's commercial operation, which has grown by 65 percent in a year.
"The growth potential is enormous," said Moura da Silva.
Mozambique's government is eyeing the project as a bellwether for the industry.
"We have made infrastructure one of our four investment priorities," said Transport Minister Carlos Fortes Mesquita.
"Thanks to this investment, the country recorded a strong growth in the railway sector."
Eight new "rail corridor" projects are now under way in Mozambique, all funded with private capital, as the state grapples with a long-standing cash shortage.
As a result, a handful of large companies, attracted by Mozambique's vast mineral wealth, have taken the lead in developing the country's rail infrastructure.
"Today the Nacala line only exists because of coal. But once the mine closes, who will be able to justify continuing operations?" asked Benjamin Pequenino, an economist at the University of Cape Town in South Africa.
"The private sector won't continue to invest if it knows it will lose money," he said.
Carimo, who remains close to the ruling party, now heads up the "Zambezi Development Corridor".
Carimo, who closely follows developments on the project, has vowed that "his" line will not only be used to carry minerals but will stimulate activity across the region it serves.
"I hate coal but I want this infrastructure to relaunch agriculture in Zambezi province," he said, adding that the region was "one of the richest in the country in the 1970s."