RHB HG 1/2

HG 1/2
Numbering:	1-4
Number:	4th
Manufacturer:	Aarau, SLM
Year of construction (s):	1875, 1900
Retirement:	1930, 1949
Axis formula :	A1z
Gauge :	1435 mm ( standard gauge )
Length over buffers:	1-3; 6900 mm 1–3 conversion; 7250 mm 7580 mm
Fixed wheelbase:	1-3; 3000 mm 4; 3030 mm
Total wheelbase:	1-3; 3000 mm 4; 3030 mm
Service mass:	1–3; 21.5 t (23.5 t conversion) 4; 24.2 t
Friction mass:	1–3: from 1877 10 t 1–3; after conversion 11.5 t 4; 11.8 t
Top speed:	12/15
Impeller diameter:	1050 mm
Gear system :	Riggenbach
Number of drive gears:	1
Number of brake gears:	1 (from 1886)
Size gears:	1-3; 820 mm 4; 775 mm
Number of cylinders:	4; 2
Cylinder diameter:	4; 220 mm
Piston stroke:	4; 180 mm
Cylinder d. Gear drive:	1-3; 300 mm (after modification 320 mm) 4; 320 mm
Piston stroke gear drive:	500 mm
Boiler overpressure:	10 Atm (old boiler 1–3) 12 Atm (4 + new boiler 1–3)
Number of heating pipes:	133 (old boiler 1–3) 131 (4 + new boiler 1–3)
Heating pipe length:	2350 mm (old cup 1–3) 1342 mm (4 + new cup 1–3)
Grate area:	1 m²
Evaporation heating surface:	50.4 m² (old boiler 1–3) 49.5 m² (4 + new boiler 1–3)
Water supply:	1–3; 1.7 m³ 4; 2.4 m³
Fuel supply:	0.5 t (coal)
Gradient:	93.6 ‰

The four cogwheel steam locomotives that were built for the Rorschach-Heiden-Bergbahn ( RHB ) are designated as HG 1/2 . For the opening of operations on September 6, 1875, Niklaus Riggenbach's workshop in Aarau delivered three locomotives. The first three locomotives were initially pure cogwheel locomotives, but received an auxiliary adhesion drive in 1877. A fourth locomotive with a slightly different design was delivered by the Swiss Locomotive and Machine Factory in Winterthur in 1900. The locomotives were given the company number 1-4 and were designated with H before 1922 .

As a result of the electrification of the line in 1930, two machines were immediately scrapped, while the two remaining were kept in reserve until 1949. All four machines were scrapped after being scrapped. The steam locomotive H 2/2 No. 3 "Rosa", which is still available at RHB today, is the former works locomotive of the Rüti machine factory .

Technical

Number 1-3

The locomotives had a Stephenson control with an upper control shaft and vertical screw adjustment.

The locomotives had an inner frame. This was supported by leaf springs on the two running axles. Between these axes, roughly in the center of gravity of the machine, was the drive axis, on which only the drive gear was located. Initially, the teeth of the drive gear were designed as hardwood combs. On both sides of the drive gear, two transmission gears were screwed into which the gears of the crankshaft engaged. The gear ratio between these gears was 1: 2.4 (diameter 900/356 mm, 50 mm pitch, 56/23 teeth). The twin drive machine acted on the outside of the crankshaft on the crank, designed as a wheel, with a counterweight, which was also the brake disc for the band brake. The crosshead was guided on two rails. The cylinders were arranged overhanging in front of the front barrel axis and had no piston rods running through the front.

The boiler was mounted horizontally on the locomotive frame and had a steam dome . The water level indicator was arranged laterally in the middle of the boiler. The spring balance safety valve was located on the steam dome, the rotary valve regulator was housed inside. This was operated by means of a handle wheel and a three-speed spindle. The fireplace had a hinged attachment.

In addition to the band brake, the locomotives also had a counter-pressure brake from the Riggenbach system and a vapor barrier that worked automatically when the speed was exceeded . A four- block block brake acted on the rear wheel and a Klose type vapor barrier acted on the train.

After an accident involving the ARB in 1885, an independent or second (brake) gear was prescribed from 1886. This was attached to its own axle, which was installed behind the rear axle. Therefore, the water tank located there at that time had to be moved to the side next to the boiler.

In order not to have to be moved to Rorschach station by another steam locomotive, an auxiliary adhesion drive was installed in 1877. This acted on the front barrel axis and was designed to be coupled. The clutch was actuated by means of steam.

The locomotives received a new boiler between 1902 and 1903, which corresponded to that of the number 4 delivered in 1900. The cylinders could also be enlarged due to the increased steam pressure.

Number 4

The steam locomotive delivered in 1900 differed in many details from the first three, although the main dimensions had not changed much. So here the brake gear was on the rear axle.

With the boiler, the experiences made in the meantime by the industry were implemented and the boiler pressure was able to go from 10 to 12 atm. increase. The three old locomotives between 1902 and 1903 also received an identical boiler as a replacement boiler. The first three locomotives were rebuilt in 1910 and many details were adapted to the number 4.

The auxiliary adhesion drive was also solved differently: it now consisted of its own small drive that worked on the first axle, the coupling of which on the jackshaft could be engaged and disengaged with steam. The drive could be started via its own steam valve, while the reversal was connected to that of the gear drive, which ran in adhesion mode. Because of this auxiliary drive, the machine was given the designation HG 1/2 in 1922

The front load of number 4 was 55 tons.

Number table

number	Construction year	Manufacturer	Serial number	modification	2nd boiler	Discarded
1	1875	Aarau	6th	1886/1910	1903	1949
2	1875	Aarau	7th	1887/1910	1902	1930
3	1875	Aarau	8th	1887/1910	1903	1930
4th	1900	SLM	1287	-	-	1949

literature

• Alfred Moser: The steam operation of the Swiss railways 1847-1966 . 4th updated edition, Birkhäuser, Stuttgart 1967, pages 356–363, 369 (6th edition ISBN 3-7643-0742-0 )
• Contribution by Hans Hug, Stephan Frei, Die Rorschach-Heiden-Bergbahn. in: Eisenbahn Amateur 9/2009, ISSN  0013-2764 , pages 452-456