The Bachmann On30 flat car deck appeared to need only a primering of flat white and a black stain to be weathered. I was disappointed with the initial result.
The over texturing in the molding did not look right. It looked more like a tree trunk than flat car decking. If viewed from the side it looks like a zebra.
The molding in the deck was too coarse to make a good looking weathered wood deck.
A fixture was made from a piece of wood to support the deck while it was being reworked. Holes were drilled to clear the truck lugs.
A razor blade is used to scrape the excess texture off of the deck. It is faster than sanding and makes a better surface. Scrape off about 90% of the rough texture.
After removing the factory texture apply a wood graining with 50 Grit sandpaper. Draw it in line with the boards.
Re-establish the board line with a scriber. The back side of a #11 blade in a hobby knife produces better results.
Roll the board edges around the car side. Use a hobby knife.
I use flat white primer and a black stain to make plastic look like weathered wood. Here I am using white craft paint and Dye-na-flow black fabric paint. It is black with no brown or blue.
Primer the deck with the flat white. Add a small amount of water so that it flows into the grooves. Paint it unevenly.
Paint the deck with the Dye-na-flow. Add water to make it moist enough to flow into the grooves. Let the stain mottle on the surface.
Do the whole deck. More color can be added to make it darker and more water to lighten. The Dye-na-flow is water soluble and can be redone.
Excess stain can be drawn off with a brush applied to the puddle.
The deck will dry lighter than when wet.
The finished deck under layout light.
The Bachmann On30 flats have a molded area that makes the end beam look wrong. Use a hobby knife and a #11 blade to work the place at the red arrow into the end beam texture.
An HO flat car deck using this technique