Bulgarian State 4-6-0 Locomotives in Bulgaria

Class 08.09 (Locobase 1587)

Data from See also "Bulgarian Railway Locomotives," Railway Engineer, Volume 33, No. 12 (December 1912), pp. 386-388.

In contrast to Maffei's adoption with modification of a Bavarian State design for the BDZ's first eight express Ten-wheelers (as discussed in Locobase 1586), the balance of the class shows no significant detail differences between the P3/5 N of Bavaria (Locobase 5924) and the BDZ locomotives.

The Bulgarian author of the RE report commented that the balanced four-cylinder compound express locomotive was "probably the most efficient class of steam-locomotive built. Weight for weight, it compares in power development with any locomotive." Using a "different form of valve", one of the class developed 1.61 HP per 121.4 lb (55 kg) of loaded locomotive weight.

Acknowledging that the bar frame contributed to a lighter weight (and thus a higher ratio), the author nevertheless asserted "it may be doubted if any American locomotive can show such a result - which is due largely to great refinement of the details."

Typical performance was pulling 350 tons on the level at 56-62 mph (90-100 kph) and at 30 mph up a grade of 1 in 100 (1%).

Class A-1/08.01 (Locobase 1586)

Data from See also "Bulgarian Railway Locomotives," Railway Engineer, Volume 33, No. 12 (December 1912), pp. 386-388.

Although it had relatively small drivers, this was considered an express engine in Bulgarian service. Its design was derived from the prototype of the Bavarian C V de Glehn compound produced in 1896 (Locobase 5925). The De Glehn system put two LP cylinders outside and driving on the first coupled axle and two HP cylinders inside to drive on middle coupled axle.

The RE report on this class claimed that the accompanying illustrate brought "into prominent relief the great defect of the divided arrangement, i.e. the long outside receiver pipe between the two groups of cylinders." If one were to build de Glehn compounds, he argued, express passenger engines were the "best possible" application because the steam "has already served once and its temperature is thereby reduced more nearly to that of the atmosphere before it is exposed to the cooling effects of the outside position."

The A-1 shared many of C V's dimensions and was produced by the same builder. But there were differences.

The Bavarian's steam dome was placed well forward just behind the stack and the sand dome stood over the gap between the second and third driven axles. The A-1's steam dome was located above and just ahead of the second driven axle while the sand dome was placed just ahead of the first driven axle.

The BDZ engine had thick plate frames in the front truck above which was a tapered sheet-metal fairing over the HP cylinder. The C V prototype used a bar-frame truck and exposed the HP cylinder more prominently.