Learn what a yellow signal means in Train Sim World, when to brake or acknowledge AWS/PZB, and how British, German and US aspects differ.
A yellow signal in Train Sim World is a cautionary or restrictive aspect, not normally a command to stop at that signal. Reduce power, begin braking as needed, acknowledge any cab warning, and be ready to stop at the next signal or meet a lower speed. Exact meaning depends on the route and signalling system.
Why has the signal turned yellow?
The dispatcher is warning that the line ahead is not fully clear at normal speed or that your route requires a reduced speed. This is normal signalling rather than a fault with Train Sim World.
Common causes include:
- A train is occupying the next block or one farther ahead.
- The next signal is at red because the route has not cleared yet.
- A junction is set for a diverging route with a lower permitted speed.
- Approach control is deliberately holding a signal at a restrictive aspect until your train slows.
- In Free Roam, the selected path or junction arrangement does not provide a clear route through several blocks.
What should you do at a yellow signal?
Pass the yellow only after preparing the train for the restriction or possible red signal ahead.
- Read the complete aspect. Check whether it is a single, double, flashing or combined yellow, and look for speed displays, route indicators and accompanying signal lights.
- Reduce power and brake early. Your aim is usually to stop safely before the next red signal, not to stop at the yellow itself. Heavy freight, poor adhesion and descending gradients require an earlier response.
- Acknowledge the warning when required. British AWS and German PZB respond differently, so use the correct control for the train and route.
- Watch the next signal. Do not assume it will clear before you reach it. If it changes to a less restrictive aspect, accelerate only after confirming the new indication and any applicable speed limit.
The HUD's upcoming-signal icon is useful for planning, but it can simplify complex aspects. Read the actual lineside signal, speed indicators and cab equipment rather than relying on colour alone.
Does yellow mean the same on every Train Sim World route?
No, Train Sim World models several national signalling systems, and yellow does not have one universal interpretation.
| Signalling system | Typical yellow indication | Required response |
|---|---|---|
| British | A single yellow normally warns that the next main signal is red. Double yellow gives earlier warning; flashing yellows can indicate a diverging route. | Acknowledge AWS if it sounds, control the speed and prepare to stop or take the indicated route. |
| German | Yellow may form a distant caution or reduced-speed aspect. The full combination of lights, boards and indicators determines its meaning. | Acknowledge a PZB-relevant restrictive indication and follow the applicable braking curve and speed restrictions. |
| North American | Yellow commonly means an approach or another restrictive indication, but definitions and permitted speeds vary by railroad and signal system. | Follow the route-specific aspect, displayed speed and cab-signal rules rather than assuming British practice. |
How fast should you drive after a yellow signal?
There is no single Train Sim World yellow-signal speed. A British single yellow does not itself prescribe one fixed speed; you must choose a speed that lets you stop before the next signal, accounting for distance, gradient, train weight and braking performance.
Other systems may attach a specific speed to the aspect through signal combinations, illuminated numbers or speed boards. Those restrictions take priority over any general rule of thumb.
Do you need to acknowledge a yellow signal?
You must acknowledge it when the fitted warning or protection system requires a response.
On many British routes, a non-green signal produces an AWS warning horn. Acknowledge it promptly, but remember that cancelling AWS does not cancel the need to brake. Missing the acknowledgement can cause an emergency brake application.
On German routes, a restrictive distant indication may activate the 1000 Hz PZB supervision. Use the acknowledgement control and then obey the braking curve; our practical guide to PZB acknowledgement and braking covers the sequence in detail. Do not treat acknowledgement and PZB release as interchangeable controls.
Can you pass a yellow signal?
Yes, a yellow signal normally authorises you to pass it, subject to any indicated speed or route restriction. The danger is approaching too quickly and then being unable to stop before the next red.
If the signal ahead remains red, stop before it and wait for authority or a changed aspect. In Free Roam, an unset destination or incorrectly positioned junction can prevent the route from clearing; see our explanation of setting routes, junctions and signals in Free Roam. Never pass a red merely because you expected it to clear.