The Pennsylvania Railroad wanted to accommodate a larger grate area in Atlantic locomotives in order to be able to burn anthracite and fragments thereof. For this purpose, three locomotives were procured on a trial basis, which had a combination of Wootten and Belpaire fireboxes and were designed as Camelbacks. The special shape of the firebox and the combustion chamber resulted in 218 square feet of direct heating surface and a grate surface of nearly 70 square feet. A visual highlight was the common cover of the steam dome and the sandpit, which looked like a huge steam dome. 

The approximately 410-ton express trains between Philadelphia and Atlantic City could be transported over longer sections at an average speed of around 55 mph. With only 260 tons on the hook, an average speed of 70 mph was achieved on the 58 miles long, slightly descending section from Camden to Atlantic City.

Ultimately, however, the PRR was bothered by the fact that the engine driver and the fireman had difficulty communicating. Hundreds of other Atlantics were procured as a result, but all of them with a conventional firebox and cab at the rear end. The three engines were sold to the Long Island Railroad in 1901 and scrapped in 1911.