My task was to create a background for passing train shown through nodal pan camera motion. The middle section was not to be visible, since it would be fully obstructed by the train - therefore less attention there. The idea was to have significantly different moods on each side of the shot - connection of weather fronts if you like. I have matched the 3d model of the train tracks into the perspective and rendered it out in 3ds Max. The rest was comped in Photoshop including integration of the tracks with the snowy ground. The painting has been revised down in Platige before the final version of the shot was approved.
Check out the gif animation for the main stages.