Trainworx 40215-01 N Scale 40' Corrugated Trailer WM 701482
40-foot trailers are still widely used as inter-rail containers. 40 foot is a good length to fit on a 50 foot TOFC flatcar as they provide some room on both ends for safety and sloppy loading. They generally come with a 96" width and are rated for 55,000 pounds. They were never as popular as 48 foot trailers because of the more limited load size. Even 48 foot trailers gave way to 53' models when the laws governing highway transportation changed.
Box vans are known as such for their rectilinear proportions. Their simple design makes them easy to manufacture and maintain.
The Western Maryland Railway (reporting mark WM) was an American Class I railroad (1852-1983) which operated in Maryland, West Virginia, and Pennsylvania. It was primarily a coal hauling and freight railroad, with a small passenger train operation.
The WM became a property of the Chessie System holding company in 1973, although it continued independent operations until May 1975 after which time many of its lines were abandoned in favor of parallel Baltimore and Ohio Railroad lines. In 1983 it was fully merged into the Baltimore & Ohio Railroad, which later was also merged with the former Chesapeake and Ohio Railroad into the Chessie System, which is now renamed as CSX Transportation.