TIMS showed obstacle detected in the Rear M1 car, 'B1' train doors.Staff (KTB) checked and confirm ed 'B1' train doors in the Rear M1 car did not open and late r isolated the defective train doors. ~~~~~ 1614 TIMS showed B1 train doors obstacle detected. Staff (KTB) confirmed 'B1' train doors did not open. Isolated the defective train doors. CE: Unable to board  1614 B1 LHS door roller delaminated - Replaced. Tested door operation for open/close, timing - OK. Door close gap 63.5, No DIR illuminated. Checked J-rsi, weather strip - OK. Kamar/Anand/Lee PT/Sugu 45097