The LS7 Class is a Class of heavy switchers with an 0-12-0 wheel arrangement that were designed by Gustav Othmar at the Eastern & Atlantic's Richmond works.
Around the large marshaling yards at both ends of the Main Line, Miami and Boston, huge trains had to be assembled regularly, including the Diamond and the Freightman's Friend. These trains were so large that two or even three 0-6-0 or 0-8-0 switchers had to be used to assembled them. This wouldn't do so the large LS7 Class was designed.
Initially, 25 of this class were built at Richmond in 1942, 20 going to the two large marshaling yards at both ends of the line and the rest being spread throughout the system in similar large yards. The performance of the locomotives was looked on with baited breath, and they performed well to everyone's relief. However, the large type was simply not in huge demand. Smaller switchers could get the job done well enough in most yards so the LS7s were confined to the largest yards on the system.