Pax feedback to staff (MSL) air discharge sound at both front and rear M2 cars. TC confirmed no abno rmality, train performance - ok. MR pressure - 10 bar.Staf f (CCK) confirmed continous air discharge sound emitting fro ~~~~~ L3 
Fault was duplicated in depot. In pit, when MR was charged up, loud air leak observed at the M2-M2 coupler. Air leak rate was 1 bar / 2 mins.
From ER, LMRG was not triggered in mainline. No EB was applied.
Based on fault reporting, MR was able to sustain in mainline.

A. MR Pipe Air Connection Gasket defective
Likely
Gasket for MRP connection at coupler face found flattened.

Air leak sound was continuous when train was coupled. Leak stopped when MRICs in both M2 isolated and resumed when cock normalised.

No leak when train was uncoupled. Operated individual couplers, no leak in coupled/ ready to couple positions.

This suggests that the air leak is from the main reservoir air pipe (MRP) connection when the valve tapet is depressed.

- Replaced the MRP connection gaskets at 2555 and 2556.
- Preventively replaced the Uncouple Pipe connection gaskets.

Additional checks
After depot shunting, there was no air leak sound from the M2-M2 cars. Leak rate was 0.8 bar / 5 mins. After rectifying air leaks, leak rate was reduced to 0.5 bar / 5 mins.


Done by: Koh, Rizman and Sanip