The train journey from Karuizawa to Saku is primarily served by the limited express trains known as the Super Azusa and the Azusa. The Super Azusa operates at speeds up to 130 km/h (81 mph), making the journey in approximately 30 minutes with a few essential stops. Meanwhile, the Azusa services offer a slightly more leisurely ride, taking about 35-40 minutes to cover the same distance, with additional stops along the way such as Shinanomachi and Sakudaira. Both trains provide a comfortable seating arrangement, with options for reserved and non-reserved seating. Notably, the Super Azusa is favored for its quicker travel time, appealing to travelers prioritizing speed, while the Azusa serves those looking to explore more of the region with its slight detour. Amenities generally include luggage space and vending machines for refreshments.