The kids start by experimenting with different things they find near the ramp: Legos, blocks, balls, cars. Some go slow but stay on, some go fast but often slide right off. After figuring out that the cars/trains go fast and often stay on, a pretend play game emerges around taking turns using the railroad crossing as the turn taking device, which had been a challenging point of conflict previously.
Taking turns sliding down
Ramp is closed. Time to make a new track.