SO B 2/3

This article deals with the series that was delivered directly to the SO, for the other locomotives of this type on OS and other JS predecessor railways, see OS B 2/3 .

SO B 2/3
Numbering:	SO 21-26 JS 74-79 SBB 1074-1079
Number:	6th
Manufacturer:	Koechlin
Year of construction (s):	1868-1870
Retirement:	1805-1907
Axis formula :	1'B
Gauge :	1435 mm ( standard gauge )
Length over buffers:	14 050 mm
Fixed wheelbase:	3500 mm
Total wheelbase:	3500 mm
Empty mass:	36.7 t
Service mass with tender:	48.0 t 51.0 t (after conversion)
Friction mass:	20.9 t
Top speed:	70 km / h
Driving wheel diameter:	1670 mm
Control type :	inside
Number of cylinders:	2
Cylinder diameter:	420 mm
Piston stroke:	560 mm
Boiler overpressure:	8.5 atü 10 atü (after conversion)
Number of heating pipes:	177 155 (after renovation)
Heating pipe length:	4100 mm
Grate area:	1.3 m²
Radiant heating surface:	6.1 m² 6.9 m² (after renovation)
Evaporation heating surface:	115.8 m² 106.8 m² (after renovation)
Water supply:	5.5 m³ 7.0 m³ (after conversion)
Fuel supply:	2.5 t 4.0 t (after conversion)
Brake:	Vapor barrier, from 1888 Wegner compressed air, from 1895 Westinghouse brake
Locomotive brake:	Counter vapor barrier
Train brake:	from 1888 compressed air brake
Train heating:	from 1889
Speedometer:	from 1889
Control:	Stephenson

The Association des Chemins de fer de la Suisse Occidentale ( SO ) procured a total of 6 type B 2/3 steam locomotives with a tender in 1868 and 1870 , which were designed as mixed-train locomotives . They were supplied by the Koechlin machine works in Mulhouse. The purchase price is given as 52,900 Swiss francs.

Technical

The machine was of the Stephenson long boiler type. The fire box was located behind the driving axles, on top of which there was a safety valve . The machine had an inner frame. The boiler had a steam dome on which there was another safety valve. The external engine took hold of the front drive axle. The drive rod was on the outside of the coupling rod pin. The internal control was of the Stephenson type. The reversal was carried out using a screw and wheel. There was a counter-vapor brake . The piston rods were carried forward. On the boiler there was a sand dome , the downpipe of which led in front of the driving axis. All the feathers were above the frame. The sheet metal was deep and had wheel protection boxes.

During the re-boilering, the tenders were set up for larger company supplies. The weight of the machine did not change significantly, although the new boiler was now approved for 10 atm instead of an operating pressure of 8.5 atm . The machines were also given a proper driver's cab, albeit one that was open to the rear. This replaced the "Lunettes" front walls with a small weather roof.

In the two-axle tender with an outer frame, the springs were outside the frame above the axle bearings. The spindle handbrake acted on the eight brake blocks on the tender axles. A direct vapor barrier also acted on these blocks until the compressed air brake was installed. Between 1888 and 1890 the locomotives were equipped with a Wegner compressed air brake that acted on the tender axles. In 1895 it was replaced by a Westinghouse brake.

Between 1889 and 1890 the locomotives were retrofitted with a steam heater and speedometer.

designation	SO no.	SO / SOS no. from 1870	JS no. from 1890	SBB no. from 1903	Surname	Factory number machine	Serial number of the tender	Construction year	Manufacturer	2nd boiler	discarded
from 1873: II from 1887: A2T from 1902: B 2/3	1 1	21st	74	1074	Moléson	1085	645	1868	Koechlin	1892	1905
	2 1	22nd	75	1075	Yes you	1086	646			1888	1905
	3 1	23	76	1076	Fleurier	1087	647			1891	1907
	26th	26th	79	1079	Montreux	1276	777	1870		1891	1905
	27	27	77	1077	Colombier	1277	778			1890	1907
	28	28	78	1078	Morat	1278	779			1889	1904

Notes: ¹ The renumbering to 21–23 was carried out in 1870 by the SO.

business

The locomotives were assigned to the workshop in Yverdon.

swell

• Alfred Moser: The steam operation of the Swiss railways 1847-1966 . 4th updated edition, Birkhäuser, Stuttgart 1967. S. 204ff