Film exposure issues

[jay2vern]

Hello all, this is my first thread, and hopefully the start of many more!

I've just delved into the world of film, and there are some shots of the London underground which are pretty much unusable. The rest of the shots (some underground even!) are perfectly fine. I'm really hoping that it's nothing wrong with the camera I'm using (a Canon A-1 with a slightly eroded mirror, which technically shouldn't affect the image). I just need to know about the problem, but ways of fixing it would be absolutely great. Thanks!