Snap:3628 Door slow opening. ~~~~~ 3627 - TC reported Rear DT car one pair of train door was not opened. Staff (KTB) checked and confirmed, Rear DT car all train doors opened normally, however B4 train door was slow in opening. CE checked 3627 - TC reported Rear DT car one pair of train door was not opened. Staff (KTB) checked and confirmed, Rear DT car all train doors opened normally, however B4 train door was slow in opening.  #3628 B4 door RHS outer roller damaged. Changed out both LHS and RHS door rollers to iron rollers and function test ok. Mating strip, push pull force, DSS, DLS red line, DLS lock nut and top rubber all checked ok. Done by: Rizman / Sanip 45260