A detailed and grunged SP Dash 8.

The steel beams are obviously styrene and the strapping is dental floss with magic market for color.  Weather is merely pigment.

Textured rust on the green car is make up sponge and grunge paint. The blended rust on the bulkheads of other cars is oil thinned with Tyrpenol applied with a brush.  All cars also softened with pigment before sealing with Dullcote.