I see one on each side (and a train ticket dropped on the ground).
If you look carefully on the far left (compare with the far right, where there isn't one) you can see the original ramp, positioned so that the handrail blocks the handlebars of any normal-shaped bike. It has an excellent grippy surface, but was basically unusable. Once this (and the left-handed wheeling thing) were pointed out, the other two were retrofitted.