The class H of the Federated Malay States Railway refers to a total of 60 light, meter-gauge Pacifics. The first seven were built by Kitson from November 1906. Others followed from Nasmyth, Wilson & Co., six of which went to the Johore State Railway. While the latter were also handed over to the FMSR, further series were created by Kitson and Robert Stephenson.

Since the later deliveries were somewhat heavier due to stronger frames and had further differences in details, the three series were subsequently named H¹, H² and H³. The H¹ were withdrawn between 1929 and 1934. Of the newer machines, many were classified as class 501 by the Malayan Railways in 1946.

The state railway of the Dutch East Indies on Java had the challenge of moving heavy loads on cape-gauge mountain routes with a maximum axle load of 9.5 tonnes and curve radii of up to 140 meters. To solve these requirements, Hanomag proposed a tank locomotive with six coupled axles in one frame in order to be able to avoid building a Mallet with its disadvantages. Among these disadvantages were listed the tendency to slip, flexible and long steam lines, greater complexity of the running gear and unstable mounting of the boiler.

In the locomotive developed as a result, the four inner coupled axles were all firmly mounted in the frame. Only the first and sixth coupled axles could be moved laterally by 30 mm according to the Gölsdorf system, and the leading and trailing axles could be deflected laterally by 100 mm as Adams axles. The water tanks were drawn low between the frames in a new way. Now the boiler could be placed higher without raising the center of gravity to improve accessibility for maintenance.

Schematic drawing with dimensions

Locomotive Magazine, August 1912

The last batch was built by Werkspoor in the Netherlands. The total of 24 examples built were the first of only two types with the axle configuration 2-12-2T in history, which is why this wheel arrangement is also known as “Javanic”. On the route for which the locomotives were developed, there was a high level of wear on the wheel flanges. They were then moved to another mountain route that had bigger curve radii. There they did very well.

To eliminate the need for double-heading express trains, the FMSR ordered 20 Pacifics from Kitson, which were delivered in 1921. They had a superheated boiler with Belpaire firebox and were among the more powerful meter gauge Pacifics.

During World War II, the Japanese brought five of the locomotives to Burma, but they returned after the war ended. They soon became class 531 and some remained in service until 1971. The 531.01 was the only one that was preserved and is now in front of the National Museum in Kuala Lumpur.

The classes K¹ and K² refer to a total of eleven Pacifics of the Federated Malay States Railways, which were built in 1927 and 1929. They were basically an improved version of the class L which had been delivered by Kitson in 1921. In 1927, Beyer, Peacock & Co. delivered seven and two years later Robert Stephenson & Co. delivered four more.

Robert Stephenson variant

flickr/Historical Railway Images

Since the letter K had been occupied by a single other locomotive until recently, the class was initially called “New K”. Later the two series became K¹ and K². During the Second World War, six were probably brought to Siam by the occupiers. The remaining Beyer locomotives were decommissioned in 1958 and 1959, the Stephenson ones only in the 1970s with the end of steam traction in Malaysia.

To accommodate increased mail traffic, the meter-gauge Federated Malay State Railways ordered class O Pacifics from North British at the end of the 1930s. Due to individual batches built between 1938 and 1946, they were given the designations O¹ to O⁴. They were built to achieve the greatest possible power with a permitted axle load of 11 3/4 tons.

These were the most advanced Pacifics in the FMSR. Lightweight construction was used in many places so that the boiler and engine could still be sufficiently dimensioned. The boiler pressure was chosen to be relatively high at 250 psi to increase power. Three cylinders were also used, which were enlarged by half an inch in the third and fourth series. Other special features were thermic syphons and a rotating valve gear.

They were successfully tested for possible high-speed traffic at 70 mph or 113 km/h, but were not actually used. Although these locomotives were later converted to run on oil, they were soon replaced by diesel locomotives in the fast mail service. They therefore continued to be used in freight transport for a long time.

In 1896, Neilson & Co. delivered two small 4-4-4T tank locomotives to the Burma Railways, which were designated class C. These had a axle load of less than eight tons and were fairly flexible with two two-axle bogies. They were oil-fired, but also had a small coal reserve. Their large firebox in relation to the tube heating surface indicates that they were well suited for commuter traffic with rapid acceleration and many stops.

In 1900, Burma Railways received five meter-gauge Fairlie locomotives from Vulcan Foundry. They had two bogies, each consisting of three coupled axles with same-size cylinders. Their difference compared to earlier Double Fairlies was that they had two separate boilers which were not joined by a common firebox. This layout was sometimes called “modified Fairlie” in this time, but had nothing in common with the Modified Fairlies built for the South African Railways more than 20 years later.

Their fireboxes were of the Belpaire type and had Drummond cross water tubes which further increased their heating surface. Each firebox was fed by one fireman, so that three people worked in the cab. Most of the time, the locomotives took a separate water tender with them.

The class N of the Burma Railways designated 17 Mallets built by North British in four batches between 1911 and 1921. With an 0-6-6-0 wheel arrangement, they had all weight available for traction. Nevertheless, they were not only intended for freight service, but also for passenger service.

Their area of operation was the Lashio branch and the Southern Shan states. Even though they had a huge pulling power, they had to be assisted by 2-6-2T locomotives on steeper sections. In 1924 Beardmore built five superheated Ns class locomotives and rebuilt the 17 others in the same form. It didn't take long until they were superseded by the Garratts starting with the GA.I.

In 1916, the Staatsspoorwegen on Java ordered 14 class C27 4-6-4T tank locomotives for suburban and passenger working from the Swiss SLM. Due to problems in obtaining the materials and getting all permits for export which arose due to the war, they were only delivered in 1918. More were built by Werkspoor and Armstrong Whitworth which brought the total to 39.

Thanks to a short rigid wheelbase and bogies which could move sideways by 70 and 80 mm, they could easily operate on curves with a radius of 120 m. To lower the center of gravity, the main water tank was located between the frames and the side tanks had a small height. In 1970, around 30 were still operating.

The Padang coal railway on Sumatra was a rack line with a gradient of up to eight percent and curves with a radius of 150 meters. It was soon found out that the 0-8-2T locomotives of the D18 class were not powerful enough to haul 200-tonne trains. The solution was the 0-10-0T locomotive of the class E10.0 designed by the Esslingen Machine Works in 1916. Production only started in 1921 and until 1928, a total of 22 had been built by Esslingen and the SLM. Between 1964 and 1967, Esslingen and Nippon Sharyo built 17 more, which were designated E10.5.

They were of the Winterthur system, what meant that they had four equally sized cylinders working in compound. But the rack wheels were driven with a gear ratio of 1 to 2.033, so the low pressure cylinders moved at roughly twice the speed of the high pressure cylinders, eliminating the need for much larger cylinders. To allow operation on the sharp curves, the first and last driving axles had some side play.