SP B-50-13/14 class boxcars.
The Sunshine Models kit does a lovely job of recreating these unique cars, right down to the neat etched ladders.
I did replace the sill steps with etched ones from my own line as well as laser cut running boards, mostly so I didn't have to deflash the resin cast ones.
To my eye I've found that Scalecoat boxcar Red II to be a good choice for the SP car colour.
The weathering was a fun departure for me.
I've been working with enamel washes from AK Interactive for a few different effects and the weathering on these cars shows some of that experimentation.
I dampen the surface with enamel thinner, then dab some of the AK colour onto the damp surface. The colour wicks along edges and flows into cracks and grooves, a little cleanup with a flat brush to get rid of the obvious blotches and we let that dry. The process takes time as each surface needs to dry before moving onto then other side and the paint needs to be fully cured so that the enamel thinner doesn't lift the colour layer(ask me how I know).
A little overspray for dust and we ready to go.
I'll be demonstrating this technique next time I get into the Trainmasters TV studio.