187 got OCs from 189 x-over.
Anyway, 189/187* x-over does not exist anymore liao. Same goes
to 106/187* too.
The cross-over is s970 to s187/189. This particular cross (S104)
still runs every weekday, although the element for crossing into
s187 seems to have disappeared.
s106 does cross-overs to 180 (AM peak) and 190 (PM peak),
different shift crosses but both are split shifts.