In 1951, North British built six 4-8-2 for the Benguela Railway which were intended for express mail trains along the Atlantic coast and in the inland between Silva Porto and Luau. In most respects they were based on the South African class 19D and were specified for hauling 500-ton trains on 1.25 percent inclines, while being suited for curve radii of 300 feet. The Benguela usually used eucalyptus wood as fuel, with bars on the tender to increase the capacity. When coal was available, it was used as fuel instead. A Kylchap blast pipe was used to increase power and decrease consumption. Their careers ended in the seventies with the civil war.

The class R-1 Mountains were the last steam locomotives ordered by the Boston & Maine. They were among the heaviest Mountains and were built in four batches between 1935 and 1941. Initially five R-1a were built, in 1937 another five R-1b, in 1939 three R-1c and finally five R-1d. All locomotives were given names that were determined in a competition.

From the R-1b onwards, the spoke wheels on the driven axle were replaced with disc wheels. The R-1c was almost identical to the R-1b, only the R-1d underwent major changes. It now had disc wheels on all drivers and the Coffin feed water heater was replaced with a Worthington one. In addition, there was now a seven-axle tender instead of the six-axle one. Thirteen R-1s were sold to the B&O in 1947, the remaining five were scrapped in 1955 and 1956.

The classes U-1-a and U-1-b of the Canadian National consisted of a total of 37 Mountains with a driver diameter of 73 inches. The a and b subclasses were essentially identical, but U-1-a designated the 16 locomotives built in 1923 and U-1-b designated the 21 built in 1924. All U-1-a and some U-1-b were built with a Robinson superheater, while the rest got one of the Schmidt design. Later, more were rebuilt to the Schmidt variant. They were retired between 1951 and 1962. Today, only U-1-a is still existing and on display at Jasper, Alberta.

In the line of 4-8-2 locomotives designated U-1 by the Canadian National, the U-1f was the last class that followed in 1944, 14 years after the U-1e. This did not only have a larger boiler and higher pressure, an increase in power was mainly achieved through internal streamlining. Like the U-1e, it had cylinders with a diameter of only 24 inches instead of 26 thanks to the higher pressure. A part was fired with oil and a part with coal.

Due to their cover on the smokebox door, they got the nickname “Bullet Nose Betty”. They were used for express passenger and express freight services. With a driver diameter of 73 inches they could run fairly fast, but some claims of 125 mph (201 km/h) have to be questioned. Number 6060 was preserved and has run in preservation over several periods. The last time it was running was between 1998 and 2011. Today it is owned by the Rocky Mountain Rail Society and currently under overhaul.

The Central Vermont operated four 4-8-2 “Mountain” locomotives which had been ordered by the parent Canadian National and leased to this railroad. Built in May 1927 by ALCO-Schenectady, they had the works numbers 67335 to 67338 and got the running numbers 600 to 603. With a driver diameter of 73 inches, they were intended for passenger trains like the “Ambassador”, but sometimes also had to haul freight trains. The 384 square feet of the firebox included a combustion chamber of 54 inches in length, 14 square feet of arch tubes and two thermic syphons with a total of 76 square feet. 

They featured Walschaerts valve gear, a stoker built by the Standard Stoker Co. and a Coffin feed water heater. The boiler pressure was later raised from 200 to 210 psi. Originally they had tenders which carried 10,000 gallons of water and 14 tons of coal. Later, they had new or modified tenders with only 9,550 gallons of water, but 18 tons of coal. Three were retired in 1956 and the fourth one in 1957.

With the development of mining in North Korea, freight locomotives were needed which could be used on the winding mountain lines. The 2-8-2 type was already used for heavy freight trains, but there were concerns about excessive wear on wheel sets and rails due to the many tight curves. Thus, a two-axle leading bogie was used and the locomotives were called "Matei", which came from the American name "Mountain".

Development took place in Gyeongseong along with the Pashiko class Pacific locomotives, and that's where the first two were built. For the other 48 locomotives, the production order was given to Kisha Seizo in Japan. The locomotives had a modern look with large smoke deflectors and a common cover for the dome and the feedwater heater. The grate of 67 square feet was fed by a mechanical stoker.

During World War II, six examples were either destroyed or stolen by the Soviet Army. After the division of Korea, some of the rest came to the northern and southern parts of the country. In South Korea they became the Mateo1, while in the North they were referred to as the Madoha class. In the north they were also used for passenger trains and their long service life can be seen from the fact that they were re-classified as series 7100 in the 1970s.

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.

One of the first railroads in the USA to purchase the 4-8-2 “Mountain” wheel arrangement was the Rock Island. In 1913, however, only the two prototypes of the M-50 class were initially delivered. They had square cylinder dimensions measuring 28 by 28 inches and drivers measuring 69 inches or 1,753 mm in diameter.

The First World War had to pass before series production came about. Between 1920 and 1924, 80 more M-50 were built in several batches, some of which were fired with coal and some with oil. They also had larger drivers of 74 inches or 1,880 mm, a larger firebox thanks to thermic syphons and a boiler pressure of 200 instead of 180 psi. Some of the coal-fired machines later received a stoker.

In 1941 seven were sold to the St. Louis Southwestern and rebuilt there. The Rock Island also rebuilt 18 of its locomotives to the M-50a. They got roller bearings on all axles, lighter connecting and coupling rods, disc drivers, a boiler pressure of 220 psi and two inch smaller cylinders that were cast in one piece along with the front frame.

The class M-67 were the first Mountains introduced into service by the D&RGW. In 1922, the press presented them as “largest passenger locomotives in the world”. To enable high average speeds over mountainous lines, they had drivers of only 63 inches or 1,600 mm. Unlike most Mountains in North America they were not connected at the second, but at the third driving axle like most Mikados. The driving axles had a wheel base of 17 ft 3 in, but a flexible bearing in the lead driving axle led to a rigid wheel base of only 11 ft 2 in.

The first ten were built by ALCO-Brooks in 1922 and numbered 1501 to 1510. They received their designation M-67 due to their tractive effort of around 67,000 pounds. In the following year, No. 1511 to 1520 were built with a trailing truck booster and designated class M-78 due to their higher tractive effort. The last ten built in the same year and numbered 1521 to 1530 again had no booster and were put into class M-67. In total they were 1,600 pounds heavier than the first ten.

Over the years these locomotives received some modifications to increase their power and efficiency. These included thermic syphons and Elesco feed water heaters. The twelve-wheel tenders already had a large coal capacity of 20 tons at the beginning, but that was later increased to 25 tons. The first M-67 was retired in 1949, but the first M-78 only followed in 1952. The last member of both classes was gone in 1955.

Between 1944 and 1947, Baldwin delivered eleven modern 4-8-2 locomotives to Colombia. They were numbered 61 to 71 and most were for the Ferrocarril Girardot-Tolima-Huila. Although they were only narrow gauge locomotives with a gauge of three feet, they had many modern features. These included a type A superheater, Worthington feed water heater, power reverser, limited cutoff and cast cylinders. The size of the cylinders was relatively small compared to the boiler, what meant that these locomotives were good for running long uphill stretches at full power.