The B-7 was a class of five 0-6-0 shunters built by ALCO in 1923. For use in the anthracite mining areas, they had a Wootten firebox with a grate area of 70 square feet. Under the new class scheme of 1945 they were designated 6S46. This represented a switcher with six wheels and a pulling power of 46,000 pounds.
Number 113 is the only operational steam locomotive of the Central Railroad of New Jersey today. It was used there until 1951 and then by the Reading Anthracite Co. until 1960. It has been refurbished since 1999 and has been used again by the Reading Blue Mountain & Northern Railroad for excursions since 2013.