The mechanic drove the customer's car onto the ramp.
I'm going to collapse onto the floor.
Rocks can tumble dangerously onto the road.
Fresh bait was being loaded onto the barge.
Many times teachers will tell you to go onto the next question if you do not know the answer.
He came onto me like he thought he was a real Casanova.
The mysterious creature jumped onto the log.
I would say that this is a great example.
When she stepped onto the stage, she was silhouetted by the bright lights behind her.
She emitted a loud cry before collapsing onto the floor.
The only plural noun in the sentence is 'rails', the singular noun is 'rail'.The sentence using the singular noun:"The thick rail provided a place to hold onto."
Example sentence - You should slow down when driving onto the off ramp of a highway.
Veronica bought red thread to sew the button onto her sweater.