Sharp Curve Flashers
Here's something that's not often modeled, but care must be taken when using it, because it's far too easy to overload scenes with blinky lights. I was reminded how I addressed this problem on my old White River & Northern IV when I noticed this almost-forgotten feature in the background of an image. Highlighted with arrows are three pairs of yellow LEDs, which flash in sequence (the lights are arranged in pairs facing at 90 degrees to one another, so they'd be seen in either direction). The fact that the lights are barely visible, and only when one peers along the street through a railroad bridge at the back of the layout keeps them from becoming overwhelming.
The lights flash in sequence, so they can be powered by any chaser light circuit.