SBB A 3/5

The Swiss Class A 3/5 locomotives were built between 1902 and 1922 for the Jura–Simplon Railway, and the Gotthard Railway. These railways were absorbed into Swiss Federal Railways in 1903. In total 111 4-6-0 locomotives of this type were built by Schweizerische Lokomotiv- und Maschinenfabrik in Winterthur, Switzerland.^[1][2]

SBB A 3/5
SBB A 3/5 express locomotive with matching coaches near Rolle
Type and origin Power type Steam Builder SLM Winterthur Build date 1902–1922 Total produced 111
Specifications Configuration: ​  • Whyte 4-6-0  • UIC 2′C v4 2′C h4 (68 locomotives) Gauge 1,435 mm (4 ft 8+1⁄2 in) Wheelbase: ​  • Engine 701-702: 3,900 mm (12 ft 10 in) 703-809: 4,150 mm (13 ft 7 in)  • incl. tender 701-702: 8,100 mm (26 ft 7 in) 703-809: 8,350 mm (27 ft 5 in) Length 18,600 mm (61 ft 0 in) Height 4,400 mm (14 ft 5 in) Loco weight 106–107 tonnes (104–105 long tons; 117–118 short tons) Fuel capacity 4-axle tender: 8 t (7.9 long tons; 8.8 short tons) 3-axle tender: 7 t (6.9 long tons; 7.7 short tons) Water cap. 4-axle tender: 17 m3 (600 cu ft) 3-axle tender: 17.8 m3 (630 cu ft) Firebox: ​  • Grate area 701-702: 2.7 m2 (29 sq ft) 703-809: 2.6 m2 (28 sq ft) Heating surface: ​  • Tubes and flues 4,200 mm (13 ft 9 in)  • Total surface 701-702: 168.8 m2 (1,817 sq ft) 703-748: 165.5 m2 (1,781 sq ft) 749-809: 157.7 m2 (1,697 sq ft) Superheater: ​  • Heating area 21 elements: 37.6 m2 (405 sq ft) 24 elements: 46.2 m2 (497 sq ft) Cylinders 4 – de Glehn compound High-pressure cylinder 360 mm × 660 mm (14 in × 26 in) Low-pressure cylinder 570 mm × 660 mm (22 in × 26 in) Valve gear Walschaerts (outside) Joy (inside)
Performance figures Maximum speed 100 km/h (62 mph) Power output 1,000 kW (1,300 hp) Tractive effort: ​  • Starting 75 kN (17,000 lbf)
Career Operators JS, SBB Numbers JS: 231+232 SBB: 701–811 Withdrawn 1926-1964 Preserved No. 705 Disposition One preserved, remainder scrapped

History

The Jura-Simplon Railway was looking for a powerful locomotive capable of hauling its increasingly heavy express trains. The A 2/4 class were unable to cope with the heavy loads, resulting in trains often being split up or double-headed, whereas the B 3/4, with its top speed being 75 km/h (47 mph), were too sluggish for express trains. This led to the creation of the A 3/5, by combining the four-wheel pilot bogie of the A 2/4, and the six-coupled driving wheelset of the B 3/4. The locomotives were designed to haul 300 ton trains on 10% gradients at 50 km/h, but the normal load could later be increased to 400 tons.^[3]

The A 3/5 was originally ordered by the Jura-Simplon Railway (JS), but only the first two locomotives were delivered before nationalization in 1903. Afterwards, the SBB ordered over a hundred more locomotives of similar design with minor modifications, ultimately rounding up to 111 members.

By the mid-1900s, the A 3/5, which were saturated locomotives, were technologically obsolete, prompting the SBB to order six experimental locomotives with advanced features in 1906. These were the following locomotives delivered in 1907:^[4]

• two three-cylinder superheated locomotives - A 3/5 501–502
• two four-cylinder superheated compound locomotives - A 3/5 601–602
• two four-cylinder saturated compound locomotives with Brotan boiler - A 3/5 651–652

In theory, the Brotan boiler locomotives cost less to maintain than conventional locomotives with copper fireboxes.^[5] These two locomotives, initially numbered 651-652, were redesignated as numbers 810 and 811 in 1913, before being scrapped in 1933.^[6]

All three variants inherited the wheelbase and wheel diameter from their JS ancestors. After extensive testing, the A 3/5 601-602 were adopted for serial production, with 47 more locomotives of this design being delivered, succeeding the JS locomotives in 1909. No.616 was exhibited at the Turin International in 1911.^[7][8]

In 1918, no.802 received a Knorr feedwater preheater with piston feed pump, while no.731 was used for experiments with oil and coal dust firing.^[7]

By the end of 1919, A 3/5s were assigned to four of the five SBB districts; only District V of Lucerne, which managed the routes of the former Gotthard Railway, did not have the JS A 3/5. District II of Basel was the home for most A 3/5 locomotives. Most of the locomotives would undergo heavy maintenance at Biel workshops, but repairs were also carried out at Zurich and Yverdon.^[7]

Distribution of locomotives, 1919

District	Administration	Main workshop	Running number	Quantity
I	Lausanne	Yverdon	701-706, 715-724, 739-742	20
II	Basel	Biel	707-714, 725-736, 760-761, 775-790, 799-809	49
III	Zurich	Zurich	737-738, 755-759, 762-772, 791-798	26
IV	St. Gallen	Biel	743–754, 773–774	14
Total quantity:				109

Preservation

One locomotive, No.705 of 1904, has been preserved since being listed in 1964, and is under ownership by SBB Historic as of 2022^[update]. It has the boiler of no.739 fitted in 1953, and the underframes of no.778 in 1963.^[2][9]

Design

The JS A 3/5, originally a 4-cylinder saturated compound design, were a further evolvement of the A 3/5 201–230 delivered to the Gotthard Railway Company in 1897, incorporating a slightly larger firebox, an increased driving wheel diameter of 1,780 mm (5 ft 10 in) and an increased piston stroke, resulting in a higher top speed of 100 km/h, compared to 90 km/h on the Gotthard Railway locomotives. Furthermore, the cylinder arrangement was rotated compared to the Gotthard machines, so that the high-pressure cylinders were arranged on the outside and the low-pressure cylinders on the inside. The locomotives rebuilt by the SBB had their wheelbase lengthened to 8,350 mm (27 ft 5 in) compared to the first two locomotives and thus a larger heating surface. The adhesion weight was increased to 46 t.^[3]

The first 48 locomotives had four-axle bogie tenders, while the others had three-axle ones, which holds a larger water capacity, but could only carry 7 tons of coal.^[7]

Models

Scale models of the A 3/5 have been produced in a number of scales, from the tiny 1:220 Z scale,^[10] up to 1:32 Gauge 1.^[1]

See also

• List of stock used by Swiss Federal Railways

References

1. "SBB A 3/5 4 Cylinder Compound Engine". Southern Steam Trains. Archived from the original on 16 January 2002. Retrieved 26 September 2009.
2. "SBB Historic steam locomotives". Railfaneurope.net. Archived from the original on 8 February 2010. Retrieved 26 September 2009.
3. Moser 1967, p. 243.
4. Weiss 1909, p. 45.
5. Weiss 1909, p. 45-49.
6. Moser 1967, p. 242.
7. Moser 1967, p. 244.
8. "Zusammenstellung der Lokomotiven auf der Internationalen Industrie- und Gewerbeausstellung" [The compilation of locomotives at the International Industrial and Trade Exhibition] (in German). Die Lokomotive. June 1911. p. 122. Retrieved 23 November 2024. (in row 42)
9. "A 3/5 705". SBB Historic (in German). Archived from the original on 10 January 2022. Retrieved 27 November 2024.
10. "Marklin Z Engines New for 2007". Legacystation.com. Retrieved 26 September 2009.

Bibliography

• Moser, Alfred (1967). Der Dampfbetrieb der Schweizerischen Eisenbahnen 1847–1966 [The steam operation of the Swiss railways 1847–1966] (in German). Stuttgart: Birkhäuser.^{[ISBN missing]}
• Weiss, M. (1909). "Neue Versuchslokomotiven der Schweizerischen Bundesbahnen" [New test locomotives of the Swiss Federal Railways: Series A 3/5 and C 4/5]. Schweizerische Bauzeitung (in German). doi:10.5169/SEALS-28085.