Yes, you can absolutely purchase train tickets at all major train stations in Lisbon, including Santa Apolónia, Oriente, and Rossio. The national rail operator, CP (Comboios de Portugal), provides several ways to buy tickets on-site: at staffed ticket windows (Bilheteiras), through automatic vending machines, and occasionally at Payshop locations within the station. For Lisbon's "Urban" (suburban) trains, you can also top up your Navegante card at Multibanco machines. It is a high-value peer tip to know that you must have a valid ticket before boarding; buying a ticket on the train is generally not allowed and can result in heavy fines, unless you board at a remote station where no ticket facilities were available. In 2026, for long-distance travel like the "Alfa Pendular" to Porto or the Algarve, it is highly recommended to buy tickets in advance online or via the CP app to secure "Promo" discounts of up to 65%.