In the dining car, Peter reads Jack's short story, which is written on stationery from the Hotel Chevalier, in Paris. The logo of the French flag on the stationery is backwards; from right to left, the colors should be blue, white, and red.
When the train attendant brings the Whitman's lemonade, Francis and Jack take two out of the three glasses she's carrying on her tray. When she leans towards Jack to apply a bindi mark on his forehead, two full glasses of lemonade are visible on the tray. Only one should be left.
When Peter reads Jack's short story on the train, the first shot shows him reading the first page. In the next shot, he is reading a different page (the page has been turned to hide the paper clip that is holding the story together). In the next shot, the first page is showing again, without being folded back.
The first time the brothers are in the dining car, the camera cuts between Francis and Peter several times. In the shots of Francis, the back of Peter's head is visible, with his hands on his temples. When the camera faces him, his hands are gone. It happens too fast for him to move his hands up and down.
It is impossible for a train to be 'lost' on Indian Railways. It is SOP to default switches on mainline routes to 'trunk' positions. All unsignaled turnouts lead to dead ends, and have to be positively signaled for a train to be advanced down the track. A mistake (or even a series of mistakes) will not get the train more than a few kilometers before it derails on an auto-stop or dead end.
While the village prepares for the boy's funeral, Francis lies down with a boy in a blue shirt kneeling beside him, and the camera travels to Peter holding a baby between two Indian locals. For 13 seconds, a Muslim call-to-prayer ("adhan") is heard, very neatly for 5 seconds. However, the boy's body is cremated the Hindu way. India has a significant Muslim population, and some people in the village may be Muslims.