I am going to use this one for a lack of a better example
DSC_4344 by
astroberkman17, on Flickr
That I did with a flashlight, and I just swiftly paint it. But I recall having to do a lot of photos over and over again. A flashlight with a far beam is ideal, here, because it allows you to stay behind your camera and light (meaning you won't get caught up in the photo).
For that photo I used one of the ever popular "buddalights"
http://www.uer.ca/...=110894&currpage=1 Because he has the fucking of a wide, less concentrated beam, and then a mode where the beam is more intense, and the reach is further. This is good for distance lighting. All flashlights with a far beam can work, though. It requires you do more "painting" (which can be difficult to get even) but at the same time it allows you to not have an issue with the foreground being overexposed.
Once you take the photo, however long it is, you will be able to see the parts you either aren't lighting enough, or need to light less, as well. In my photo, I dind't light the bottom enough, resulting in dark water.
You aren't realistically going to get the ENTIRE tunnel perfectly, but the further your light reaches, the further you can light.
You can also try using flash in various ways, but then once you walk in front of the cameras, you are risking catching yourself.
I don't know if this helps any or even makes sense...but it's how I light drains. And of course can be tweaked a bit.