Trains arrive at Kursk Station, located a little over 3km north-east of the Aquamarine Hotel, from central Russia (Kursk and Nizhny Novgorod), eastern Ukraine (Donetsk and Kharkiv), and St. Petersburg (some Sapsan high-speed services).
By taxi
It should not take much more than 15 minutes to reach the Aquamarine Hotel, although traffic at peak times can considerably extend the journey. Taxis should not cost more than $20, but if you are not prepared to risk negotiating with a driver on arrival, you can order a transfer with a driver to meet your train here.
By metro
If you prefer to use public transport, take the metro from Kurskaya Metro Station, which is connected to the mainline station, and travel west on the dark-blue line one stop to Ploshchad Revolyutsii. Change there to Teatralnaya and the dark-green line and continue one stop south to Novokuznetskaya. From there it is around ten minutes' walk to the Aquamarine Hotel.