Rear M2 A3 train door not proven closed.Opened/closed few times - ok. ~~~~~ L3 2635 ER D/L & found FC 933.
Fault occur at #2635 B1 saloon door.
Checked door isolation device condition (left/right), isolation device blocking plate, door guide for any FOD & door leaf for any rubbing marks - All OK.
Measured door resistance :
Left door - push = 6.2kg, pull = 6.4kg.
Right door - push = 5.8kg, pull = 6.2kg.
Clean bottom door guide & top J-rail.
Performed door gauge test & door cyclic test - OK.
 Chan GF/Alan. 05/02/2021.