Howard - Those look great...they really give the feel of tinplate trains, much like the old lead ones from the 1930's.
I used the middle shade of the Quickshade. Instead of dipping which can be just an awful mess, I brush it on liberally and then lightly brush away the excess. After that dries I dry-brush some highlights. Then I give it an overspray of Testors Lustre-Less Flat Lacquer.
The point of the dipping method is to quickly give the figures some shading in the crevices without the detail painting. For wargamers like myself, we use the two-foot rule, i.e if it looks good from two feet away, then it's good enough. Using block-painting and dipping you can knock out alot of figures very quickly. Some guys use Minwax Polyshade instead of the Army Painter Quickshade...I've never tried it.
Here's another one of those plastic figures I tried:
The faces really come alive if they have decent detail on them, and for me they look more realistic than if I tried to paint the features myself (not to mention the fact that the eyes are too far gone to make a job of it, lol).