An easy way to enhance the look of any diesel locomotive is to blacken the grills and vents to provide more depth.  You can use a black wash to bring out the grill or vent details.  Weathering powders are extremely effective bringing out locomotive vent and grill details.

Hopper Weathering Clinic
By Bill Mock
December 2009

Here is the first stages of weathering of my new BN [ ... ]

For the TL;DR - just scroll down an look at photos is useful since it's about architecture :) Feedback appreciated !

I want my layout to have a high level [ ... ]

My layout is called the GREAT WEST ROCKY MOUNTAIN, KENORA-SUDBURY RAILROAD COMPANY. The general scenery is modelled on my hometown, Kenora, Ontario as [ ... ]