What is feedback on an analogue controller?

Feedback on an analogue controller is a function that detects if your model train is experiencing difficulty climbing a gradient or struggling due to voltage drop, the controller then automatically applies more power to counteract the effects.

It works by detecting the reverse EMF generated by a model's motor when it's under strain and applying more power to compensate. When the strain is no longer present, less reverse EMF is produced and the controller reduces power to match ensuring that the model's speed remains constant. It's a bit like having cruise control for your model train!