I have not read Ted Sadler’s article, I used to be a professional photographer back in the days that meant getting your hands wet!
Now everybody is a photographer (or someone who takes snaps) there is a difference. Without going into the depths of how to, there is one very good tip that will improve your photographs, that is use a reflector to push light back into your subject.
In the case of shooting a picture of a loco have a piece of A4 white paper or card and lay it down in front of the subject and you will see it get brighter, you can also angle the card and prop it up with anything handy.
Get you eye in line with the lens and play with the card to get the best position, simples.
Mike