The 2-8-8-2 Mallets built by ALCO-Brooks in 1918 for the BR&P were among the heaviest locomotives in the world when they were built. They had drivers of 57 inches and cylinder diameters of 28 and 44 inches, with a stroke of 32 inches. The firebox had a grate of 99.2 square feet and a direct heating surface of 410 square feet. Additionally there were arch tubes with a total surface of 69 square feet. A Duplex stoker was installed to feed such a huge boiler. The valve gear was operated by a Ragonnet & Mellin power reverser.

They were rated to haul 140 empties or 70 loaded cars over a 1.1% incline of 17 miles. Although the railroad originally planned to order 15 of these locomotives, the first order only included seven locomotives which were delivered in March and April 1918. Two more were delivered in September 1923 which were somewhat heavier, but otherwise identical. Running numbers were 800 to 808. When the BR&P was bought by the Baltimore & Ohio in 1932, they became class EE-2a No 7316 to 7324. They were scrapped in 1950 and 1951.