Brazilian film-maker Walter Salles had a huge breakthrough success with this big-hearted road movie in 1998. It is a prize-garlanded and Oscar-nominated film that made a serious player of its director and an international name for its then 69-year-old female lead, Brazilian stage and screen star Fernanda Montenegro. She plays a querulous woman called Dora who finds herself travelling across the country, on the edge of poverty and almost on the run, from Rio to the Sertão in Brazil’s remote north-east, in the company of a bewildered, angry, vulnerable little orphan boy whose life she has just (unwillingly) saved.

It’s an often unashamedly sentimental movie about redemption in the tradition of Charlie Chaplin and Vittorio De Sica. An ingenious, if glib, final twist gives the tale its solidity, though you can taste some processed sugar in the mix; from a modern perspective it’s possible to compare this to rom-dram pictures such as Message in a Bottle and The Lunchbox. Central Station’s two characters happen to be looking for someone called Jesus; a common enough name in Brazil, of course, but the audience is entitled to suspect more, given that this man is supposed to be a carpenter and his loved ones believe that he will one day return – that is, make a second coming, back into their lives.

Montenegro’s Dora is a weary and cynical woman, a retired teacher who supplements her nonexistent pension by setting up a stall at Rio’s teemingly chaotic Central Station – naturally, a vivid image of vast, uncaring indifference – offering to write letters for illiterate people and post them. There’s an endless line of people poignantly dictating their desperate messages, but Dora has lately taken to secretly binning them at the end of the day. Salles at one point also contrives a terrific sequence showing dozens of young guys hurling themselves through train-carriage windows to get the best seats.

One day, a stressed woman called Ana (Soia Lira) asks Dora to write an accusatory letter to the man who, before vanishing, fathered her son, who she has brought with her; a moody, unhappy nine-year-old boy called Josué (Vinícius de Oliveira). Josué wants to meet his dad, but when Ana is accidentally killed in traffic outside the station, Dora “sells” this boy to a people trafficker for the price of a new TV. She then thinks better of it, steals the boy back and, avoiding the sinister people who now want to kill her, takes Josué on a desperate mission to track down his fugitive, no-good dad, Jesus, with only the address she has on the envelope to go by.

Throughout the film, Salles keeps in play a basic question: what exactly does Dora want? To some degree, she simply wants to escape the now murderous and vengeful traffickers and to annul the grotesquely evil thing she tried to do; an intelligent woman, Dora surely knew in her heart that the people who bought Josué were not froman adoption agency, as they claimed. But we are to be in no doubt that this whole incident has brought to the surface of Dora’s mind long-suppressed and painful memories of her own father, who broke her heart rather as Jesus appears to have broken Josué’s.

Salles allows us to ponder a further question: if Dora is sceptical, as we must be, that there can be no good reunion of Jesus and Josué even in the unlikely event of Jesus being found, then what does Dora envisage for herself at the end of all this? To find a new beginning on the road – even love? There is an aborted romance with a sweet-natured truck driver, who senses that joining forces with this woman and this boy is not a good idea. Perhaps Dora vaguely imagines establishing a new family life with Josué far away from Rio.

The film’s final twist makes the story close with a satisfying click, though there is something a little smooth about it; for me it works against the story’s social-realist credentials and its evident ambitions for something more mysterious and spiritually resonant. Yet there is great pleasure to be had in those fervent, crowd-pleasing lead performances from Montenegro and de Oliveira.