The high-speed Allegro first entered service on the 409 km St Petersburg – Helsinki route in December of 2010. Built by the French company Alstom and jointly owned by the Finnish and Russian Railways, the Allegro is an Sm6 trainset designed especially to be compatible with both Finnish and Russian train gauges, technical systems, and rail electrification. With a top speed of 220 km/h, it currently makes the run in 3 hours 27 minutes. As many as 4 trains run daily on this route.

The Allegro has 7 carriages – Carriage 1 is 1^st Class (aka Business Class), while the remaining Carriages are 2^nd (Economy) Class. In addition, four of the 2^nd Class carriages have special features – Carriage 6 has seats reserved for passengers with pets, Carriage 2 has seating for disabled passengers, Carriage 4 is a restaurant car (with seating for 38 passengers), and Carriage 7 has a small play area for children. Regardless of ticket class, each seat has an adjustable backrest and a folding table, and each pair of seats share a 220V socket.

1^st Class tickets include hot beverages (tea and coffee, self-service), headphones, and newspapers or periodicals. There are 48 1^st Class seats, arrange in rows of 3 (two side-by-side with a separate seat across the aisle). 2^nd Class seats vary by carriage, but there are total of 331 2^nd Class seats.