I have just bought a Nikon D40x camera and I'm knew to the hobby. I was trying to take a photo of a train from the platform coming under a bridge. The problem I had was with exposure. The tunnel and train was a strong contract in light (dark) to the sunny blue sky (light). The sun was out at 12.30 and was behind me but I could get the blue sky to show and get the train. It was either a dark train with a blue sky or the train fine but a white sky. Any tips of what I can do to avoid this?