Hohenzollern locomotives No. 447/1888 and No. 473/1888

Hohenzollern locomotives No. 447/1888 and No. 473/1888
Manufacturer:	Hohenzollern
Year of construction (s):	February 1888 and May 1888
Type :	1'A1 n2 and 1'B n2

The .. Hohenzollern locomotives No. 447/1888 and No. 473/1888 were steam-powered light railway - locomotives with conical boilers and a track width mm 600.

history

1'A1 locomotive, works no. 447/1888		1'B locomotive with a tender , factory no. 473/1888

The first locomotive with a leading axle, a driven axle and a trailing running axle was delivered to the Prussian Army by the Hohenzollern Locomotive Works in Düsseldorf in February 1888 with the serial number 447 as a narrow-gauge locomotive . However, it turned out to be completely unsatisfactory as it lacked performance and it could only drive an hour to the next water tank.

Therefore, in May 1888, Hohenzollern delivered a second, somewhat heavier and more powerful tender locomotive with the serial number 473 with a leading axle and two driven axles.

Type of construction and their properties

The strongly conical boiler (English: launch-type boiler ) was installed in such a way that the upper edge of the truncated cone was horizontal. The purpose of the conical shape was to increase the water depth above the firebox , the hottest part of the evaporation surface . The fire box and pipes were placed in the lower part of the mantle, with the pipes running upwards parallel to the lower edge of the cone. One difficulty was that the steam room in the boiler was insufficient, so an enlarged dome of almost the same capacity as the main mantle was required.

Since the boiler was to be made as simple as possible, rolling a conical shell and adding a large dome meant a significant increase in complexity and cost.

These locomotives and their boilers were a complete failure. They were too light and underperforming for their job, and due to their high center of gravity and their tiny wheels , they tended to derail on uneven light rail tracks . The first locomotive also had insufficient adhesion, as it only had one drive wheel set.

Although they originated a few years after Baron Arthur Percival Heywood's book on the minimum-gauge railway was published, they ignored almost all of Heywood's tenets. The boilers lacked evaporation capacity and were not designed for continuous operation.

Technical specifications

	Factory no. 447/1888	Factory no. 473/1888
design type	1'A1 n2	1'B n2
Gauge	600 mm	600 mm
Grate surface	0.2 m²	0.3 m²
Radiant heating surface	2.7 m²	8.5 m²
Empty mass	2300 kg	5300 kg
Service mass	2800 kg	6300 kg
wheelbase	1600 mm	1800 mm
Boiler pressure	10 bar	10 bar
Wheel diameter	ø250 and ø450 mm	ø350 and ø550 mm
Cylinder diameter × piston stroke	ø100 mm × 180 mm	ø180 mm × 230 mm

Individual evidence

1. ^ Two Extraordinary Steamers.
2. ^ Rüdiger Fach, Günter Krall: Heeresfeldbahnen der Kaiserzeit . Kenning, 2002, ISBN 3933613469 .