3522 having Encoder Fault. To check & re ~~~~~ 3522 having Encoder Fault.(Train Prep).  3522 encoder replaced. Normalised/resealed ECOS. Found BCU COMMS fault. Swapped TRC4B Card to #3521 cab & fault still persisted. Swapped Encoder to #3521 & fault transfer. OPS 20 raised to replace Encoder on #3521. Encoder S/N (After Swapped) : 1040/035 (#3522)    1007-010 (#3521)  Aminur/Azmi/Zaidi 44374 To replace 3521 Encoder.  3521 Encoder replaced. Function test - OK. #3521 Encoder S/N : OLD : 1007-010 NEW : 9938014-CB  Khairul/Aminur 44374