Th16

KFNB Vd 414 ʻBistrizza‘ (Sigl 1393/1872), location and date unknown. In 1906 this locomotive became kkStB 51.27 and later went to PKP, to be withdrawn before 1931. Source: www.commons.wikimedia.org.

Side drawing of kkStB class 51 with class 8 tender. Source: EZ vol. 1.

ČSD 313.004 (ex KFNB 418 ‘Dürnholz’, then kkStB 51.31, Sigl 1690/1873), Vrutký, Czechoslovakia, date unknown. This engine was written off in March 1931. Source: www.k-report.net.

The k.k. privilegierte Kaiser Ferdinands-Nordbahn (KFNB), which connected Vienna with Cracow, was one of the oldest Austro-Hungarian railways: first section, between Floridsdorf and Wagram, was completed in November 1837. In early 20^th century KFNB had over 1300 km of tracks. Locomotives were initially distinguished only by individual names. In 1869 all motive power was divided into several classes (groups), designated with Roman numbers. This system was modified in 1881. Class X included 120 freight engines built between 1871 and 1889 by StEG and WLF (49 each), Sigl (fourteen) and Wiener Neustadt (eight). They featured 0-3-0 axle arrangement with drivers 1186 mm in diameter. Individual batches differed in details and five versions can be distinguished. In 1881 they were re-classed Vd (together with four class IXa engines, later kkStB class 43). All these locomotives were still in use when KFNB was nationalized in October 1906; former class X was assigned kkStB class designation 51 and all engines retaining their individual names. Typically they were coupled with three-axle class 8 tenders, built between 1871 and 1892 in several variants.

After WWI most of these already obsolete locomotives were divided between Czechoslovakia and Poland. ČSD were the major recipient, with 70 examples, of which six were withdrawn before new designation system came to use in 1925. Of the remaining 64, four (from two initial batches, delivered by StEG in 1871 and 1872) were classed 312.1. Sixty were classed 313.0 (third digit referred to maximum axle load, and later production variants were slightly heavier). Withdrawals started in 1930s, but the last engine of this type, 313.036 (ex 51.79, WLF 532/1884) remained in service until February 1965. Austrian state railways BBÖ kept only eight examples; the last one was written off in 1930. Romanian state railways CFR took over only three, which remained in use until 1934.

PKP took over 39 engines of this type, of which two (51.62 and 51.120) were written off in 1920; this implies that they had seen little service, if any. Further six were withdrawn until 1924 and nine between 1924 and 1926. Within the framework of the new designation system, which came into use in 1926, they were classed Th16, but most probably this applied only to 22 examples that were still in the company’s rosters at that time. Assignment of service numbers to individual examples is not known. Th16s served mainly in southern and south-eastern Poland and due to moderate axle load were suitable for secondary lines with weaker tracks. All were withdrawn until 1931. No locomotive of this type has survived until today.

Main technical data

No.	Parameter	Unit	Value
1.	Years of manufacture	-	1871 – 1889
2.	Total built / used in Poland	-	120 / 39
3.	Tender class	-	10C16
4.	Axle arrangement	-	0-3-0
5.	Design maximum speed	km/h	45
6.	Cylinder bore	mm	2 ´ 435
7.	Piston stroke	mm	632
8.	Engine rating	kW/hp	270 / 365
9.	Tractive effort	kG	7 000
10.	Boiler pressure	MPa	1.12
11.	Grate dimensions	m X m	1.9 / 1.94^4)
12.	Firebox heating surface	m^2	9.3^1)-3) / 9.1^4)5)
13.	Distance between tube plates	mm	4 110
14.	Number of flue tubes	-	200^1) / 195^2)3) / 192^4)5)
15.	Heating surface of flue tubes	m^2	136.0^1) / 132.3^2) / 130.9^3) / 130.6^4)5)
16.	Number of smoke tubes	-	-
17.	Heating surface of smoke tubes	m^2	-
18.	Evaporating surface, total	m^2	145.3^1) / 141.6^2) / 140.2^3) / 139.7^4)5)
19.	Superheater heating surface	m^2	-
20.	Diameter of drivers	mm	1 186
21.	Diameter of idlers front/rear	mm	- / -
22.	Total weight, empty	kg	30 600^1) / 32 000^2) / 33 000^3) / 32 900^4) / 33 700^5)
23.	Total weight, working order	kg	35 000^1) / 36 000^2) / 37 000^3) / 36 600^4) / 37 600^5)
24.	Weight on drivers, working order	kg	35 000^1) / 36 000^2) / 37 000^3) / 36 600^4) / 37 600^5)
25.	Weight with tender, empty	kg	41 600^1) / 43 000^2) / 44 000^3) / 43 900^4) / 44 700^5)
26.	Weight with tender, working order	kg	60 600^1) / 61 600^2) / 62 600^3) / 62 200^4) / 63 200^5)
27.	Maximum axle load	T	12.0
28.	Axle base (with tender)	mm	10 217
29.	Overall length (with tender)	mm	14 355
30.	Brake type	-	Hand / Hardy

Note: all data with late production kkStB class 8 tenders (PKP class 10C16).

1) 51.01 through 10.

2) 51.11 through 19.

3) 51.20 through 39.

4) 51.40 through 81.

5) 51.82 through 120.

References and acknowledgments

- www.pospichal.net/lokstatistik (website by Josef Pospichal);

- Charakterystyki parowozów (Steam Locomotive Characteristics) by A. Czeczott (Ministry of Transport, 1927);

- TK vol. 2, LP, EZ vol. 1, ITFR.