Real Time Feedback:the train door indicator at Rear M2 and Rear DT car did not light up when doors are opened. Staff(MSL) checked and conf irmed all train doors indicators are working and no abnormal ~~~~~ To further rectify.  3548/2548 both A/S & B/S external side lights replaced. Security/function test - OK. New Door External Side Lights S/N : #3548 : 009 (A/S)  008 (B/S) #2548 : 011 (A/S)  006 (B/S)  Sarma/Anand 44220 3548 & 2548 Real Time Feedback: Passenger feedback train door indicator did not light up when doors are opened. Staff(MSL) confirmed all train doors indicators are working and no abnormalities found.  3548/2548 found A/S & B/S external side lights not working. OPS 20 raised to follow-up.  Farid 44220