Pick a signal box. Keep the trains moving without making the road wait too long.
The bell rings when a train is offered. Accept it at its block instrument.
Close the road: turn the gate wheel (Bailey) or lower the barriers (Tuborne). A stalled vehicle will block this.
Road shut? Pull that train's signal lever. After the train passes, restore the lever and reopen the road.
Views (key V cycles): Window (drag to look, use the panel), Walk (WASD around the box, mouse to look, click levers, instruments and controls; at Tuborne you can walk out over the footbridge and down the stairs), Overview. Shortcuts: keys 1–4 pull levers; Bailey wheel ←/→; Tuborne barriers ↓ lower, ↑ raise.