Over the the years, most have been said about layout lighting. You can waste enormous time reading online articles, printed press and a plethora of comments without ever doing anything close to lighting your layout.
A few years ago, I added lighting in my office room to bring some life to my figure collection displays. Basically, it was a series of small projectors on a track with LED lamps. Nothing fancy, but more than enough for the task and still good looking. I was pleased by the amount of light and ease of pivoting each lamps. As you can guess, from time to time, I did display trains on the shelves and thought to myself it would be a decent way to light a small layout.
Forward a few years to yesterday. To light Jérôme's layout, which is about 13' x 11', we used three of these track lights, one for each module. This time, instead of 3000K LED, we went with daylight 5000K. At first, it looked awkward, but in a matter of a few minutes, we couldn't tell the difference. Better, color rendition on locomotives and cars was up to the task and thus we kept the 5000K lamps.
I won't go in detail, but we found out a 3-projector track light was good enough to light an 8 foot long layout module when installed about 2 feet from the fascia. Depending on module geometry more or less lights can be needed. Another positive thing is you can orient the lamps in such a way to put emphasize on certain part of the layout, which bring some life on what we see.
Another positive aspect of track lights is they don't require complex wiring, use easily available standard components, don't need to build valence and can be located anywhere in a room. That last point is important because lights to close to the fascia cast very unrealistic shadows on model. With track lighting and no valence, you can locate the lights were they are more optimal. They look good and deliver a substantial amount of light economically. We spent about $110 on fixtures and LED bulbs to light about 20 linear feet of layout which is quite decent given the results.
I wouldn't be surprised we will soon update certain parts of Hedley-Junction to take advantage of this new lesson.