Board and batten siding on passenger cars, both narrow and standard gauge was common before about 1890. The board widths varied from 8" to 12", with the batten usually about 2" wide. One spec I have seen calls for popular boards with cottonwood battens (for the Gilbert and Bush built New York Elevated cars which were shipped to the Richmond Shipyard Ry. (SF Bay) during World War II. ) We also see lots of this on West Coast narrow gauge cars, both those built locally, by the Carter Brothers or Kimball, and those built in the east by Jackson and Sharp Barney and Smith, or Harlan.
Randy Hees