The S-1 was the standard freight locomotive of all Canadian National predecessors from 1913 onwards. It was a Mikado with 63-inch drivers and 27 by 30-inch cylinders. The subclasses S-1-a to e were used by the Canadian Government Railways and were only built by Canadian manufacturers. The Grand Trunk operated classes S-1-f to h, which also came from US manufacturers. After these batches were built until 1918, it was not until 1926 that the CN had two more S-1-j built. Three locomotives were preserved, of which only 3254 was operational until 2012. The 3377 had before been dismantled to provide spare parts for 3254.

A few years after the revolution, China Railway developed a Mikado that would be built in large numbers. The chassis of the JF1 class, which had been built since 1918, was used as the basis. It received a modern boiler and was also adapted to current requirements in other areas. The new class was called JS or “Jiàn Shè”, which roughly means “construction”.

With a coupling wheel diameter of only 1,370 mm, a high level of traction could be achieved. As is usual for China, the tender was chosen to be large with a coal supply of 17 tonnes. The design came from Dalian, but the production was subcontracted to several plants.

The first 1,135 units were built between 1957 and 1965. Another production only started in 1981, which included almost 800 more locomotives until 1988. More than half of them belonged to a “B” variant, which received some improvements. A special feature was a locomotive that was sold new in 1989 to the Boone and Scenic Valley Railroad in Iowa.

These Mikados were based on the JF6 and were developed for industrial tasks. With a construction period up to 1999, they were the last large series-built steam locomotives in the world. There are reports that some locomotives were still in use in 2016 in open-pit mines or in heavy industry companies. Accordingly, an extraordinarily large number have survived to this day. Between 1989 and 1991 three US tourist railways ordered brand new locomotives of this type, one of which was lost at sea. One machine was also delivered to South Korea in 1994.

The K-27 class was the last compound locomotive built for D&RGW. The “K” stood for “Mikado” and the number for starting tractive effort of 27,000 pounds. Its engine had four cylinders and was of the Vauclain type, but was replaced by a simple two-cylinder engine just four years after delivery. As with other narrow-gauge locomotives of the D&RGW, the axles were in an outer frame. The nickname “Mudhen” came about because with the original engine they often derailed. Most K-27s were scrapped in the fifties and the last two built still exist today. The No. 463 runs on the Cumbres & Toltec Scenic Railroad and the No. 464 is owned by the Huckleberry Railroad and last ran in 2019.

As the penultimate series of steam locomotives for the three-foot gauge, the D&RGW procured the K-36 from Baldwin, ten of which were delivered in 1925. The “K” in the designation stood for the Mikado design, the number for the tractive force in thousands of pounds. As with its predecessors, the coupling wheels were mounted inside the outer frame and the coupling and connecting rods, valve gear and cylinders were attached outside the frame. The balancing weights were not integrated into the wheels either, but mounted on the outside.

The K-36 was initially used only in front of freight trains. In 1937, three examples were fitted with steam heating and communication lines for use in front of passenger trains. Three more followed in 1945, leading to more than half being equipped accordingly. One locomotive was so badly damaged in an accident on the turntable in 1955 that it could only be used as a spare parts donor. The other nine were removed from active service with D&RGW between 1962 and 1970.

No. 481 IN October 2014 in Silverton, Colorado

Wayne77

It is unusual for a steam locomotive from the 1920s that all nine engines which were not destroyed in an accident are still preserved and eight of them are still operational. Five of these are now owned by the Cumbres and Toltec Scenic Railroad, four of which are in regular service. The other four are now owned by the Durango and Silverton and are also used regularly. One of each of the two operators was converted to oil firing around 2020.

As the speed of steam locomotives increased, the moving masses of the engine became an ever greater problem. Although this could be partially compensated for with larger and larger driving wheels, the practical limits were reached with a wheel diameter of 2,300 mm. Regular operation could no longer be achieved above a speed of 400revolutions per minute, which was achieved with the locomotives of the classes 05 and 61 at around 175 km/h.

The steam motor, which works in a similar way to a piston engine, was seen as a possible way out. Since this had been developed into a compact design in the mid-1930s, the idea arose to develop a steam locomotive like the modern electric locomotives of that time with individual axle drive. Apart from the motors, the locomotive was created according to the same pattern as other express locomotives, since the focus was initially on the steam engines and no further experiments were wanted. The four powered axles each received a steam motor, which was mounted alternately on the right and left outside the wheels. These each had two cylinders arranged in V shape with a 90 degree angle to each other. Since significantly higher rotational speeds were possible here than with conventional steam locomotives, the wheels were designed with an exceptionally small diameter of 1,250 mm.

In order to avoid the development of a new boiler, the boiler of the class 44 freight locomotive was used. This was one of the first mass-produced locomotives with a pressure of 20 bars and promised good performance. At the projected speeds, a streamlined fairing was mandatory, and the fairing of the 01¹⁰ didn't need too many adjustments to be used on the 19 1001.

After the somewhat delayed delivery, extensive test runs took place, but due to the war, these mostly took place at speeds below 100 km/h. Despite this, some high-speed braking tests were undertaken, reaching speeds of up to 186 km/h. Although the axles reached almost 800 revolutions per minute, the running smoothness remained in a very good range due to the low moving masses. The disadvantage that turned out to be that the drive axles were not coupled to each other and individual axles tended to slip. On a trip with a heavy express train, the locomotive once even stopped on an incline.

In times of war, no further attention was paid to further development and the single locomotive was used in passenger service from the beginning of 1943. During a shutdown due to damage, it was severely damaged in a bomb attack in October 1944 and was no longer used. After the end of the war, road number 19 1001 was taken to the USA together with class 52 with a condensing tender in order to be able to examine the latest German developments there. The Bundesbahn subsequently decided not to buy them back, because even the network, which was still in a poor condition, could not use a single unit that was expensive to maintain for these speeds.

The last passenger locomotive that was still designed by the Prussian State Railways was to be able to pull heavy express and passenger trains on low mountain ranges without double-heading. The drawings were made as early as 1919 and represented the most powerful passenger locomotive of all Länderbahnen. They were put into service by the Reichsbahn and they soon became the class 39.

Like the G 12, the P 10 also got a bar frame and a Belpaire firebox. This had a trapezoidal floor plan, as it was wider at the back than the frame and lay between the coupled wheels at the front. The three cylinders each had their own valve gear, resulting in double eccentric rods on the left side. The second coupled axle was driven, but the valve gear was actuated by the third.

Sectional drawing with dimensions

Die Lokomotive, December 1923

In order to achieve sufficient running properties for the top speed of 110 km/h, the first coupled axle could be moved laterally by 35 mm and was connected to the leading axle to form a Krauss-Helmholtz bogie. The second coupled axle had weakened wheel flanges, the third could be moved by 25 mm and the fourth was fixed. Lateral play on the trailing axle was 100 mm.

The locomotives could pull 780-tonne express trains on the level or 825 tonnes at 30 km/h at one percent. However, their field of application was restricted by the fact that the axle load was more than 19 tonnes, contrary to the original plans. As a result, they could only be used on certain main routes and many locomotives had to be parked for some amount of time after their delivery. In addition, the firebox often struggled with the air supply, so that the boiler's performance could not be fully utilized.

On the Bundesbahn, the tenders were replaced with newer 2'2' T 34s with a coal capacity of ten tonnes. In order to solve the problems with the air supply, the blast pipe on 39 119 was modified. This increased boiler output by 42 percent, giving steam production of 18 tonnes per hour and a drawbar power of 2,000 hp. It is unclear whether more were rebuilt, this could possibly have affected 54 machines. They were decommissioned by 1967. The Reichsbahn reconstructed it as class 22, which received a completely new boiler.

The wheel arrangement 2-8-2 was chosen for fast freight trains in order to be able to achieve the required power with an axle load of 18 tonnes. With a driving wheel diameter of 1,600 mm, 90 km/h could be achieved and the axle load of the driving wheels could be changed to 20 tonnes by switching the position of bolts. The boiler pressure was initially 20 bars, but had to be reduced to 16 bars because of the problems with the St 47 K alloy. After the war, the Reichsbahn and the Bundesbahn fitted their class 41 locomotives with new boilers. They were in use in the GDR until 1988.

The East Broad Top operated six Mikados, all of which survive to this day. The oldest of these is No. 12, which was christened “Millie”. Like her newer sisters, she had 48-inch diameter drivers, but was lighter and had smaller cylinders. When the EBT was reopened in 1960 as a complete heritage railway with all its equipment, number 12 remained in service with three of her sisters until she had to be retired in 2000 due to wear and tear. After the railroad had reopened in 2020 under new ownership, the locomotive remains inoperable and it remains to be seen if she will be refurbished.