The echelonretex.zip file you have requested: Ship Textures / Federation / Echelon retexture - 557.55kb is not available. Perhaps try browsing all files for the game Star Trek: Bridge Commander and upload any files you want to share or are missing. This is the only information we could locate:
This retextures the TOS era Echelon class to a more TNG era ship. There is one of each picture below so you can compare them. The Echelon ship mod (required) Can be found under federation ships.