TC reported that when train stop at platform, service brake at car front DT and front M1 is 'Off'. ~~~~~ 1681 TC reported when train stop at platform, service brake at is 'Off'.  "1681 propulsion control unit swapped with 1682. Limited movement - OK. Brake test and all brake able to release/apply at coast/braking. Depot shunting, all brake operation - OK.                 3681    3682,, Charging Time : 2:3     1:59,, Cut Out       : 10.2    10.2,, Cut In        : 8.4     8.3,, Leak Test:    : 0.4     0.4,, Chan GF 44391 TO CONDUCT M/L TEST  1681 BCU replaced. Depot Shunting, no brake fault illuminated. Checked All brake pressure - all within criteria. 681/682 ML test for "Brake O ' recurrance - OK. Lee PT/Shafie 44392