To replace 3723 gateway valve ~~~~~ 3723 To replace gateway valve.  3723 gateway v/v replaced. Brake pressure test - oK. OPS20 raised for M/L testing. 3723 Gateway V/v S/N : OLD : 1801046 NEW : 1948060  Chan GF/Selvan 44071 To conduct main line testing.  723/724 M/L test - Passed. Powering/braking current - OK. All cars regen brakes registered. Wheel slip observed at 1st 3 stations due to wet track. No reoccurrence at the following stations. To further monitor during revenue service.  Kana 44073