RUH is five terminals in two groups: T1–T4 sit in one connected complex and T5 (domestic, plus Saudia/Flyadeal hubs in the current layout) stands apart. The Yellow Line has three different airport stations (T1-2, T3-4, T5); alighting at the wrong one means a shuttle or inter-terminal walk before you even leave the airport.
The airport shows Line 4 airport service around 06:00 to midnight. A 01:00 landing into a metro-priced budget is really an app-car or taxi landing, at several times the fare. RPT does not publish an airport timetable you can rely on months ahead.
The gate readers take contactless Visa/Mastercard/Apple Pay, but the official pages never say one card can pay for a group — a second tap will look like an unfinished journey and jam the gate. Each adult needs their own card, phone wallet, darb card or app QR ticket.
The airport's own FAQ states drop-off/pick-up zones allow 5 minutes free, after which a violation fee of SAR 575 applies for exceeding the standing time. Friends circling to 'meet you at Column 11' rack this up against the designated pick-up areas.