Magyar Allamvasutak 4-6-2 Locomotives in Hungary

Class 301 (Locobase 1551)

Data from "Pacific Express Locomotives for the Hungarian State Railways," Locomotive Magazine, Volume 18 (15 February 1912), p. 33; and "New Compound and Simple-Expansion Engines, Hungarian State Railways", Railway Engineer, Volume 36, Nos 3 and 4 (March and April 1915), pp. 70- , 105-110.

Built to haul 600-700 ton trains over the Transylvania mountains, these engines were the first in Hungary to use the deGlehn divided drive frequently used in four-cylinder engines. Unlike most deGlehn types, however, these admitted live steam to all four cylinders. In this design the inside cylinders were laid out slightly ahead of the outside ones and drove the leading axle.

After trials with the first two, 18 more followed in 1913 to work the Buda-Pest to Bruck-Viralyhida and Buda-Pest to Marchegg sections 15 went to Romania in 1919.

Class 301.500 (Locobase 1552)

Data from "New Compound and Simple-Expansion Engines, Hungarian State Railways", Railway Engineer, Volume 36, Nos 3 and 4 (March and April 1915), pp. 70- , 105-110. See also A E Durrant The Steam Locomotives of Eastern Europe (Newton Abbot:David & Charles, 1966), p 40.

Trialled in comparison with the 301.001 simple-expansion engines described in Locobase 1551. These were the only two compounds built.

RE's analyst's first argument in the two-part report beginning March 1915 was the use of the term "de Glehn" compound to describe the setup. Double-drive crank arrangemens (also simply called divided drive) were first adopted by M. Henry on the French railways in 1888 and de Glehn's supposed innovation was in fact a "still popular fallacy."

He then reported the prevailing view of compounds in Europe (and even more in the USA, Locobase notes) was that the introduction of superheaters had negated most of the compound engine's advantage in efficiency. Moreover, to achieve the same power in a compound as in a superheated simple engine entailed "such a high steam pressure that the coal economy is not worth the excessive under-cylindering of the compound

This contention was also fallacious. His detailed set of comparison showed, he argued, "that compound engines may be so designed as to be but little more efficient than the best designed of modern simple engines." Or, he continued, "on the other hand, they may be designed to be 25% more powerful with each cubic foot of steam used at any given pressure." His math suggested such a design would "thus economise 25% of fuel per drawbar horse-power, or per ton mile."

Discussing the differences between a well-designed compound such as the Swedish State Railways F class Pacific (Locobase 2477) and simple-expansion locomotives designed for 1.900 BHP performance, RE's extended analysis noted that the simple engines required about 20% more area than that needed for compounds of the same boiler pressure. Observing dryly that "British engineering journals supposed to treat of progressive locomotive design" never paid attention to such problems. the analyst looked to experts abroad. These pointed out that "copper is an expensive metal and at about 22% greate weight of copper in plates and stays is put into the fireboxes of simple-expansion engines, which have to burn 20% to 25% more coal per hour to produce the same power as compound engines of the same boiler pressure."

Continuing his defense of compounds, the writer added that "consumptio of copper by burning (plates and stays) is also greater annually, as well as the first cost, with simple expansion."

After the dissolution of the Austro-Hungarian Empire in 1918, 1 was transferred to Romania while the other said in Hungary.