Yes, you're absolutely right - an assistant especially with this kind of camera would have been amazing but no, I was travelling all by myself. Luckily this was an "alighting only"-platform on the DLR and at this time of the day trains are coming only all 10 minutes or so. Time enough for me to take another quick shot without any humans on it. This time I used a monopod (you know these "tripods" with only one leg?) which makes taking photos in this position a lot easier. Unfortunately you need a permission to take professional photos on the tube (which I didn't have) - and this kind of camera looks quite professional though I'm not a professional photographer...
Very good work to get low and use the low angle for this shot.
I like the symmetry. I don't like the rist you took, getting so close to the tracks. I hope you had a friend/assistant to tell you if a train was coming!
Don't get to see this place so deserted very often! You've achieved a very dynamic image from something so familiar, with those converging lines, light and tones, shrouded by wonderful curves.