The 4HHHH4m19y Class is a class of huge articulated locomotives designed by Gustav Othmar at the Eastern & Atlantic's Charlotte Works.
The Eastern & Atlantic was always looking to have the largest and most powerful locomotives for its extremely long and heavy drag freights. Even with classes like the 2JJ2m9yf Class, the road still needed bankers on some of it's extremely hilly routes. The railroad began to start to look for a locomotive that did not need assistance, and thus looked for the largest locomotive possible.
In the 1910's, Baldwin had researched the idea of a quadraplex locomotive, or one with four sets of driving wheels. While this locomotive was unsuccessful, Gustav Othmar had an idea to make it successful. He decided to have two boilers on the same locomotive.
The 4HHHH4m19y Class proved a challenge to build, even more so than the road's triplexes that were already in operation at the time. The design had two cabs, one at one end of the locomotive and the other cab at the other end of the locomotive. The two boilers met in the middle, but they did not touch each other. Rather, they were spaced a distance apartment to allow for curves. The very front and rear locomotive units were attached rigidly to the boiler structures, while the inner two were not.
The class was useful on the extremely long drag freights and coal trains in Virginia and the Northeast, and two were produced in 1933.