Guys, I'm trying to do a simple 'train through a dark tunnel' feature (like the ones in Well). I've got the train moving happily around a loop (prop_dynamic parented to a func_tracktrain). The problem I'm having is the the prop (bomb_cart.mdl in this case) is always light as it appears in its initial position. What I want to happen is that it comes out of a dark tunnel, gets brighter as it passes the player standing on the platform, then as it disappears down the tunnel, it gets darker again. Looking closely at the trains in Well, when they are in the tunnels either side of the map, they are darker. Once they come out into the sunlight, they brighten up. Therefore it does seem to be possible to achieve the effect I want. Can anyone please suggest what I'm missing to make this work? Cheers EDIT: The screenshots show the train as it first appear in the dark tunnel, yet it is still brightly lit. The lighting stays constant all the way along the tunnel.