New Delhi, Aug. 13 -- Leaked documents have revealed secret details about Vladimir Putin's private train. This train is reportedly used exclusively by the Russian president.

The revelations come from the Dossier Center, a London-based investigations group. It's backed by Mikhail Khodorkovsky, an exiled former Russian oil tycoon.

Documents were reportedly leaked from an insider at Zircon Service. This company outfits train carriages for the Russian president's office.

While Putin's train use is publicly known, most of the carriages remain secret. The Kremlin has shared images only of an ornate boardroom carriage.

One specific carriage, numbered 021-78630, houses remarkable luxury facilities. A glossy brochure describes it as a combined...