A description is presented of the facilities of the HYTRAN language and its implementation as the HYTRAN Operations Interpreter which are critical to its effective use in conjunction with ECSSL. As indicated, the HYTRAN language provides a powerful tool for hybrid simulation, and has been implemented to be widely available on a number of hybrid systems. As hybrid systems and simulations develop, the language and the Interpreter will be able to easily develop with them. The combined ECSSL/HYTRAN system enables simulation descriptions in the CSSL language to be as transportable as FORTRAN programs.