The foreign force patrolled every mile of the line, routing Renamo saboteurs. Guns clutched ready, its soldiers also rode in the carriages, a reassuring presence for those who still braved the line.
Four years of peace make a difference. Today, as we pull out from Beira station - an enormous, soulless building left behind by the Portuguese - and chug across the endless miles of mangrove, the only would-be terrorists are tiny boys who run from villages of thatched huts to level imaginary machineguns and spears at the passing train.
With the 16-year civil war over, the track, which was laid a century ago by the British to link land-locked Rhodesia to the sea, is no longer a military target. Once again it carries the hope of prosperity, but this time Mozambicans - not their colonisers - may gain.
The Beira Corridor project is almost complete and aims to revive the fortunes of the line, the port and the region. The war left Mozambique bankrupt and wholly dependent on foreign aid - with Beira and its hinterland particularly badly hit. European donors have financed the dredging of the harbour, the overhaul of the dilapidated port and the building of an oil terminal. Beira, with bags of spare capacity, is now struggling to lure trade from Durban and lucrative Zimbabwean freight. Progress is slow.
Passengers are delighted with investment in the line, and travel to and from inland villages to buy fresh produce which then finds its way back to market. Some travel all the way to the border to buy cheap Zimbabwean sugar and butter which they sell at a profit at home.
Peace means the journey is taken with a lighter heart. But in the packed, chocolate-brown carriages used since the days of the Portuguese, war still haunts the psyche.
The locals gossip about a famous female Renamo guerrilla leader, made immune to bullets by a traditional healer. Before leading her men into battle she would strip naked and her troops would take turns to crawl though her legs. This ritual apparently spread her invincibility.
That peasants still believe in the power of medicine men is not surprising.
One man whispers that their magic is so potent they can make a women menstruate for a solid 12 months. But the carriage's urban professionals are believers too. A hush falls over the carriage as a teacher, a devout Muslim, talks of a terrorist attack in which carriages were derailed and passengers killed. The carriages, he says, still lie by the track. "At night you can still hear people talking and the train moves," he says. I laugh, convinced he is joking. He shakes his head gravely. "Maria you should believe. Such things happen here."
From the start, the line took lives. When it was laid, hundreds died from dysentery, malaria and attacks by wild animals.
Today Joaquim Lucio, 45, is a passenger. But for 20 years he has driven trains from Beira to Zimbabwe. Before it was defended by Zimbabwean troops, he remembers the line was a target for Ian Smith's Rhodesian regime. When Renamo stepped in as chief saboteurs, every journey Mr Lucio made might have been his last. At certain points, he tells fellow passengers, his hair stood on end and the blood raced. The medicine man was about all there was left to turn to. If Renamo did not get you, the government surely would.
"You were scared even to be sick," he says. "If you had to stay off work Frelimo would think you were a Renamo supporter and come and take you to jail.
"Then there was always a chance that Renamo would ... kidnap you to stop you operating the trains. That happened to some friends." Five of them died.
And he remembers the time before the war when the white Rhodesians came down to Beira in their thousands to lie on the beaches, eat the famous prawns and have sex with the prostitutes.
But Mr Lucio never took the Rhodesians to the coast. "Only white Portuguese engine drivers were allowed to work on those trains," he says. "They said that we Mozambicans lacked skills but even the ticket collectors had to be white."
The Portuguese bought the line in 1949 and showered luxuries such as fridges and stoves upon train drivers. The trains ran at twice the speed they can today, for the track and rolling stock were in good repair. Today carriages are filled to bursting and people spill over into corridors; poor tracks make journeys tortuously slow.
There is much for a train enthusiast like Mr Lucio to miss as Beira struggles to rise from the ashes. But not the arrogance of the British and Portuguese.
"When the Portuguese left they said the trains would soon stop running and that we Mozambicans would never manage on our own," he says.
"Well they went and we managed - and the trains are still run today."