Somebody read and adapted Ringworld. Also unless I missed it, they fudged the part where the trains transition from the static tracks to the rotating structure

Somebody read and adapted Ringworld. Also unless I missed it, they fudged the part where the trains transition from the static tracks to the rotating structure. If so, that speaks volumes to their level of attention to detail. Did anybody pick up what the lit up pit in the middle was supposed to be?