The 11D-57 engine was developed as part of an N-1 performance upgrade (N-1M).  Russia's original N-1 moon vehicle relied entirely on LOX / kerosene propulsion systems.  As a result, a larger vehicle and more stages were required to deliver less total payload to the vicinity of the moon than the US Saturn V.  To improve the "robustness" of the N-1 vehicle, the 11D-57 LOX / hydrogen engine was developed as a replacement for the NK-31 / 39 LOX / kerosene engine.   For the N-1M, the third and fourth stages would be converted from LOX / kerosene to LOX / hydrogen - greatly improving payload capability.  Unfortunately, the N-1 program was cancelled while the 11D-57 was in qualification.  As a result, only two or three engines remain today (in museums).  However, GenCorp Aerojet is marketing a newer version of the 11D-57, redesignated the AJ26-57A.