Although the 0-4-4T wheel arrangement was mostly found on small Elevated railroad locomotives in the USA, there were also larger examples. The Chesapeake & Ohio received two from Schenectady in 1889, which they designated as class B-1. With a service weight of 110,000 pounds and cylinders measuring 17 by 24 inches, they were significantly heavier than most Forneys. One locomotive was sold to J.T. Gardner and the second was scrapped in 1913. Later the class designation was used for new locomotives with a 2-10-2 wheel arrangement, which came to the C&O via the Hocking Valley.

The F-16 class Pacifics were designed to haul express trains of 700 short tons over graded routes. They were similar in many respects to the ALCO No. 50,000, designated the Erie K-3 class, but were built by Baldwin. With a driver diameter of only 73 inches, they were well suited for the inclines. They were brought up to date over their service life, for example by installing a stoker. After the Second World War they could still be found in local traffic.

After various Mallets with the wheel arrangement 2-6-6-2, the C&O had the class H-7 built with the wheel arrangement 2-8-8-2. In 1923 and 1924, 25 H-7 were delivered by ALCO and in 1926 20 H-7a by Baldwin followed, which had a slightly higher adhesive weight. Since, unlike their predecessors, they worked with simple expansion, they were called “Simple Simons”.

By 1935 they received a boiler pressure of now 215 instead of 205 psi and thermic syphons. The 632 square foot firebox heating area now included 145 square feet from the combustion chamber and 165 from the thermic syphons. They could haul a 9,500 short tons freight train 113 miles in five hours.

They were replaced on the flatter lines by the class T-1 2-10-4 and on hilly lines by the 2-6-6-6 “Alleghenies”. 30 of the 45 locomotives were later leased to the Union Pacific. The Richmond, Fredericksburg & Potomac also bought some locomotives.

In order to significantly increase speeds of heavy and fast freight trains, the C&O had the H-8 class developed by Lima. The inspiration came from the class A of the Norfolk & Western with the wheel arrangement 2-6-6-4. A three-axle trailing truck ensured that an even larger firebox could be installed than on the existing locomotives. It was given relatively large drivers and steam heating so that it could pull passenger trains at 70 mph (113 km/h) if necessary.

The boiler was even larger than on the Big Boy and the locomotives were otherwise designed after the latest standards. With an output of around 7,500 hp on the drawbar, the locomotives were among the most powerful steam locomotives ever. The installation of a trailing truck booster was rejected because even higher tractive forces were not required. There is some controversy regarding the actual weight of the H-8, as changes during development made it significantly heavier than originally planned. The first driving axle was loaded with 86,700 pounds or 39.3 t, which was the highest axle load of any steam locomotive.

The C&O named the wheel arrangement “Allegheny” after the mountain range that had to be overcome. Here two H-8 hauled up to 11,500 short tons. There they replaced the 2-8-8-2 class H-7 and enabled approximately twice the speed for heavy coal trains. On flatter lines they replaced the 2-10-4 class T-1 and could haul up to 13,500 short tons alone.

The first 45 H-8 were built during World War II, during which time they had to haul both urgent cargo and troop transports. The Virginian had eight class AG locomotives built in 1945, which were based on the H-8. In 1948 the C&O received another 15 H-8, which were again similar to the AG. As early as 1952, the first H-8 were replaced by diesel locomotives. By 1956 they had all disappeared and today 1601 and 1604 remain preserved on static display.

At the Chesapeake & Ohio, the wheel arrangement 4-8-4 was not being called “Northern”, but “Greenbrier” after the hotel in White Sulphur Springs, West Virginia that was a famous destination of the C&O. For heavy express trains, the C&O operated a total of twelve locomotives of this wheel arrangement which were delivered in three batches between 1935 and 1948. These Greenbriers were built by Lima and formed the class J-3. They hauled famous trains like the George Washington, the Sportsman and the Fast Flying Virginian, but were sometimes also used for freight and pusher service, especially in war times.

The first batch, numbered 600 to 604, was built in 1935 and named after Virginia statesmen. They had a large modern boiler with a Worthington feed water heater, thermic syphons, arch tubes and a combustion chamber. Pressure was initially 250 psi, but later raised to 255 psi. Built with Walschaerts valve gear, they later received Baker valve gear. In addition to the 67,000 pounds of tractive effort provided by the four driving axles, a trailing truck booster raised the total to 81,000 pounds. 

Numbers 605 and 606 were built in 1942 and also named after Virginia statesmen. They got a pressure of 255 psi and Baker valve gear from the start and had roller bearings on all four truck axles. Since most high-strength steel was needed for the war efforts, Lima had to use more conventional steel, what increased the weight of the locomotives by 15 tons. After the introduction of the J-3a, these were called J-3b due to the changes compared to the first batch.

As the last 4-8-4 locomotives built for an American railroad, Lima built the last five Greenbriers in 1948. They only carried the numbers 610 to 614 and no names and due to several improvements, they became class J-3a. The driving wheels were now of the Boxpok type and had a diameter of 74 instead of 72 inches. Also the older locomotives now got 74 inch drivers. Roller bearings were now on all axles and on all other rotating parts of the running gear. The firebox lost its thermic syphons and arch types, but now had circulators, a larger combustion chamber and the flues in the boiler had an increased diameter. Instead of the Worthington feed water heater, they now had an Hancock exhaust steam injector. 

These locomotives delivered around 3,500 hp on the drawbar and had a top speed of 100 mph or 161 km/h. After all had been retired between 1953 and 1957, 614 was the only survivor. It was restored in 1980 and used as a testbed for Ross Rowland's ACE 3000 Project for a modern coal-burning steam locomotive to counter the rising oil costs. It was placed on static display at Clifton Forge, Virginia in 2012 after it had been used for excursion service. In June 2025 it was brought to the Strasburg Rail Road for an additional restoration into working order.

In order to be able to cope with the increase in fast freight trains caused by the war, the C&O ordered 2-8-4 locomotives. While this wheel arrangement is commonly known as “Berkshire” in North America, the C&O named it “Kanawha” after a river in West Virginia. The engineers called them "Big Mikes". They shared many similarities with the Pere Marquette class N, but were slightly heavier overall and had a tender with a larger capacity of coal. By 1947, a total of 90 had been built by ALCO and Lima. They all had a booster in the trailing truck. They were used not only for fast freight, but also for passenger service. The first of these locomotives were replaced by diesel locomotives as early as 1952, and by 1957 the last one had disappeared from active service. Twelve of these still exist today and number 2716 is being restored to working condition since 2019.

The class L-2 Hudsons of the Chesapeake & Ohio were 4-6-4 express locomotives introduced in 1942 to haul the fastest trains on level routes. They had to haul 15-car trains at 90 mph or 145 km/h. Trains on mountainous routes were already hauled by the “Greenbrier” 4-8-4 which had been introduced in 1935.

Their features included 78 inch (1,981 mm) drivers and a large 255 psi (17.6 bars) boiler with thermic syphons and an Elesco feed water heater. All axles of the locomotive and even the side rods had roller bearings. The Franklin type E booster was a special express variant that allowed operation up to 33 mph or 53 km/h.

The original class L-2 consisted of eight locomotives built in December 1941 and the following January. In 1948, five more of a revised design followed as L-2a. They had Franklin rotary cam poppet valves instead of piston valves and were the last steam express locomotives any US railroad purchased. After only a short career, they were scrapped in 1953.

While other railroads switched from coal to diesel, the C&O refused to take this step for a while. Given their huge coal business, attempts were made to modernize the fleet while retaining coal as fuel. In 1948 and 1949, a total of three coal-fired steam turbine locomotives were built, which were the longest single-unit locomotives in the world and were nicknamed “Holy Cow”.

In the front part of the locomotives was the coal bunker, which fed the 6,000 hp turbine in the rear part of the locomotive. The water came from an additional tender. The eight traction motors were powered by the four generators, which together delivered 4,960 hp. With this system it was hoped that maintenance would be easier than with piston steam locomotives and the aim was to complete round trips of 1,000 miles without servicing stops.

The intended area of operation was the planned “Chessie” streamlined train. With a top speed of 100 mph (161 km/h) of the locomotives, this was to be hauled at a cruising speed of 70 mph (113 km/h). The M-1's fate finally came when they turned out to be very unreliable and the “Chessie” did not come into being. They were eventually used in other areas for only a short time and were scrapped in 1950.

The C&O class T-1 was an important step in Lima's “super power” concept. It was a class of 2-10-4 “Texas” freight locomotives based on the 2-8-4 “Berkshires”, but with an additional driving axle. The idea came when the C&O borrowed a Berkshire from the Erie and thought that they needed to increase its power and tractive effort. The result were 40 locomotives numbered 3000 to 3039, which were built by Lima in 1930 with the works numbers 7516 to 7555.

The boiler had a diameter of nine feet and a grate of 121.7 square feet. The combined heating surface of firebox, tubes and superheater was more than 9,600 square feet, what was the greatest number for any two-cylinder steam locomotive ever. Boiler pressure was initially 260 psi, but was increased to 265 psi in 1933. The cylinders with 29 inches of diameter and 34 inches of stroke worked on 69-inch drivers and generated 93,345 pounds of tractive effort. Cutoff was limited to 60 percent. A booster added 15,275 pounds, leading to a total tractive effort of 108,620 pounds. 

Most locomotives of the class were used between Russel, Kentucky and Toledo, Ohio, but some also operated in eastern Virginia. With a similar tractive effort compared to the class H-7 2-8-8-2, but more horsepower, they could haul the same trains with a higher speed. Typical coal trains had 160 cars and totalled 13,500 short tons. On the return journey with empty cars, they reached speeds of 50 mph. Their downside was that the long driving wheelbase made counterbalancing challenging, so that they tended to damage the tracks on grades when ascending them with full power.

Although already introduced in 1930, the T-1 was used in the same role until the switch to diesel. They were only surpassed in power by the H-8 “Allegheny” 2-6-6-6, but were still able to maintain their position. In 1942, the PRR took this design to create its class J-1, of which 125 were built at Altoona. Compared to the C&O locomotives, these had cast-steel frames with integral cylinders. In 1948, No. 3020 was lost due to a boiler explosion. The others were retired and scrapped in 1952 and 1953.

When hauling the new steel passenger cars over the Allegheny Mountains, the class F-15 Pacific locomotives quickly reached their limits, so that the trains could not consist of more than six cars. As a remedy, a new type of locomotive was designed in which, compared to the Pacific, a fourth driving axle was added and the diameter of the wheels was slightly reduced in order to obtain more adhesive weight, to be able to install a larger boiler and to increase the tractive effort. Since this was the first locomotive with a 4-8-2 wheel arrangement in North America, the C&O gave the design the name “Mountain”.

Compared to the F-15, the tractive effort was almost doubled and the indicated power significantly increased. Ten steel cars with a total weight of around 600 tons could now be hauled over the Alleghenies without any problems. With this load, they could reach 25 mph at 2.52 percent, and even 70 mph were reached on the flat. However, a disadvantage of the smaller drivers and the special design of the Walschaerts valve gear was that the engines exerted a very high hammer blow on the rails. As a result, only three class J-1 locomotives remained and from then on significantly more powerful Pacific class F-16 and F-17 locomotives were procured for the same task.

During World War I, the J-1 had to haul heavy freight trains across the Alleghenies. After the end of the war, seven examples of the USRA Heavy Mountain were procured and designated class J-2. These put less strain on the rails with larger drivers and Baker valve gear and, due to the increased boiler output, were able to generate approximately the same pulling power.

In the 1920s, the J-1's valve gear was optimized with the help of new knowledge in order to reduce the known problems. In addition, the J-2s were soon fitted with Walschaerts valve gear and were then referred to as the J-2a. Two were built new and five USRA locomotives were rebuilt. In the 1930s and 1940s they were overtaken by the new J-3 and L-2 class locomotives, which initially led to the J-1 being phased out by 1948. Shortly thereafter, the C&O passenger trains were converted to diesel traction, which also meant that the J-2 was retired by 1952.