How do I check for faults on model railways?

Here are some tips for checking for faults on model railways:

Visually inspect the tracks. Look for any debris, dirt, breaks, kinks, or corrosion on the rails that could interfere with electrical contact or cause a derailment. Gently clean the tracks with cleaning fluid if needed.
Check that all sections of track are properly connected. Any gaps in the circuit will cause issues. Gently push joiners or rail connectors together to ensure a solid connection.
Test the locomotives and rolling stock on a section of track without any points or accessories. They should roll smoothly. Listen for any grinding or binding and watch for jerky movements.
Inspect the wheels and axles of locomotives and wagons. Make sure wheels are clean and turn freely without wobbling. Check for any debris or damage.
Examine any locomotives that stop unexpectedly on the layout. This is often caused by a faulty motor, dirty track/wheels, or poor electrical pickups on the locomotive trucks.
Check wires and connections between power packs, points, accessories and the track. Reconnect any loose wires.
Look for burn marks or melted areas on the bottom of locomotives. This can indicate a short circuit.
Use a multimeter or continuity tester to check for continuity in the track and locomotives electrical pickups. Isolate sections that do not have continuity.
If using DCC, check for issues with the command station, throttles, decoders and program track. Reset components if needed.