Change a line's platform or enable alternatives

What to do

1. Choose the affected line, then hover its station stop row in the lower section. Confirm the station and direction first, especially when the same station appears more than once in the stop list.
2. Use the move-stop action in that row or the HUD to select the intended primary terminal. Terminals are otherwise assigned automatically based on reachability and utilization. Check the route preview after changing the primary.
3. Open the alternative-terminal control and select only the backups you want this stop to use. While moving a stop, the plus above a terminal in the world can also add an alternative. This is a setting for that stop, not a promise that every line at the station will use every platform.
4. For trains, find the last signal before the station: with the line window or manager open, the manual identifies it by a blinking arrow in the line color. Verify every enabled alternative can be reached from that decision point, including the required crossover.
5. For road vehicles the decision point is the station entrance; for ships it is the waiting point outside the harbor; for aircraft it is the runway end. Inspect the relevant approach rather than applying the train-signal rule to every carrier.
6. Read any terminal warning before testing. Alternative paths appear more transparent in the preview. Watch an arriving vehicle when the primary is occupied and inspect whether it can use the selected backup without leaving an arrival or departure connection error.

How to tell it worked

The intended primary and alternatives remain selected, their approaches are valid and arrivals can use a configured backup when the primary is occupied. A backup remaining unused while the primary is free does not show failure.

If you are still stuck

Empty alternative ignored: confirm it is enabled for this exact stop and reachable from the decision point. Red terminal warning: use the arrival/departure arrow in Select Terminals. Queues persist with valid alternatives: inspect the shared station throat or access road; adding platforms does not remove every approach bottleneck.