Forma	Para…	Ejemplo
going to	planes e intenciones; lo que ves venir	I'm going to buy presents. / It's going to rain.
will ('ll)	decisiones del momento, promesas, opiniones	I'll make the tea. / I'll write, I promise. / I think you'll love it.
present continuous	citas y planes ya organizados	We're going to the fete this afternoon.
present simple	horarios y calendarios	The train leaves at one.

La última ya la has visto de pasada: para horarios — trenes, vuelos, clases, películas —, el inglés usa el present simple, igual que el español: El tren sale a la una → The train leaves at one.