The Santarem to Santo Tirso route primarily operates on regional trains, specifically the Alfa Pendular service, which connects various cities across Portugal. The Alfa Pendular trains reach speeds of up to 220 km/h (137 mph) and typically take around 2 hours and 45 minutes to cover the journey, making stops at key stations including Lisbon and Vila Nova de Gaia. This high-speed service is known for its balanced speed and comfort. In contrast, the Intercidades service primarily serves the route but usually travels at lower speeds, with a journey time of about 3 hours and 30 minutes due to additional stops. Passengers can choose from different seating classes on both trains, with Air Conditioning and Wi-Fi generally available in the Alfa Pendular. The Alfa Pendular is preferable for those prioritizing speed and efficiency, while Intercidades can be a better option for those looking for cheaper fares and more stop options.