This List of Russian steam locomotive classes includes those built both before and during the Soviet era. They are to the gauge of unless otherwise stated. Some locomotives originally used in Poland during the period of the Russian Empire were built to and later converted to gauge. Class letters are shown in Cyrillic characters, followed by romanized characters in the next column. For more information, see Romanization of Russian. The main source for this list is Le Fleming and Price's Russian Steam Locomotives.
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