No, it's unlit except for the crossings under the bridges. It gets dark early there in the winter, but you'll still find people biking at dusk with headlights. A bit of advice: even though the greenbelt is safe and populated with cyclists, runners, and families (especially in warm weather), keep an eye out for vagrants. I was riding my mountain bike on one of the gravel trails with my wife and son last summer and we rode into a stand of cottonwoods. We came across a camp used by homeless people, although no one was there at the time.
There are some lights but not through the entire length.
Thanks! Your answer is awaiting moderation.