After the classes L-3 to L-5, the ten L-6a built in 1910 were the next Camelback ten-wheelers for commuter service in the roster of the Central Railroad of New Jersey. They still had 69-inch drivers, but were somewhat heavier than their predecessors and had larger cylinders. With their massive Wootten firebox and no full cab behind it, they had a very compact appearance and looked relatively short.

In 1912, ten superheated L-7s followed with cylinders of 23 instead of 22 inches. Between 1928 and 1941, all L-6a were also rebuilt to the L-7s standard by adding a superheated boiler and larger cylinders. The L-7as was created by widening the grate and again a total of ten were built in 1913 and 1914. 1918 saw the introduction of the L-8s, of which again ten were built. These were very similar to the L-7as, but had a higher boiler pressure.

All of these had been built by Baldwin and they got consecutive numbers between 750 and 789. In the new class scheme, the L-7a and L-7as became class T-38, where the “T” stood for the 4-6-0 wheel arrangement (Ten-wheelers) and the 38 stood for a starting tractive effort of 38,000 pounds. In the same way, the L-8s became class T-40. All reached the end of steam, with their retirements only occurring between 1950 and 1954.