P38 (Russian: П38) is an experimental series of 4 freight locomotives produced in the USSR at the Kolomna Locomotive Works in 1954-1955. The heaviest locomotive in the history of Soviet locomotive construction.

P38— is the factory designation of an experimental freight articulated steam locomotive of type 1-4+4-2, of the Mallet system with a simple-acting machine (single steam expansion). It is a lightweight version of the same type of American steam locomotive "Yellowstone", the most powerful in the world.

This is class P38 №0001.