Gotthardbahn 4-6-0 Locomotives in Switzerland

Class A3/5 201 (Locobase 5855)

Data from [], last accessed 19 January 2017; and Edouard Sauvage, "New Compound Locomotives for the St Gothard [sic] Railroad [sic]", American Engineer and Railroad Journal, Volume LXIX, No 9 (September 1895, pp. 419-423. (Thanks to Alexander Blessing for his detailed outline of specifications in his 30 November 2022 email. They led me to look more closely at the gotthardbahn tables and use the data there.). Works number was 877 in 1895.

This ten-wheeler is one of the two prototypes tested by the Gotthardbahn before selecting the compound passenger engine they wanted to use. It's a three-cylinder arrangement similar to that later used by Smith in Great Britain.

French locomotive expert Sauvage reported that the three-cylinder compound had been "found to be too weak." So it was "adjusted" to run continuously with a direct steam admission into the three cylinders." At the likely and considerable expense of high coal and water consumption, the result was a very powerful tractive effort of 32,155 lb (14,585 kg or 143 kN).

The four-cylinder de Glehn was the version chosen; see Locobase 5056.

Class A3/5 202 (Locobase 5856)

Data from [], last accessed 19 January 2017; and information from Edouard Sauvage, "New Compound Locomotives for the St Gothard [sic] Railroad [sic]", American Engineer and Railroad Journal, Volume LXIX, No 9 (September 1895, pp. 419-423. (Thanks to Alexander Blessing for his detailed outline of specifications in his 30 November 2022 email. They led me to look more closely at the gotthardbahn tables and use the data there.) SLM works number was 878 in 1895.

This is one of the two prototypes tested by the Gotthardbahn before selecting the compound passenger engine they wanted to use. A four-cylinder de Glehn compound design, this was the winning prototype. Its three-cylinder rival appears in Locobase 5855.

It's appropriate to include the French locomotive expert Sauvage's estimate of the design "from what I have seen":

"...the steaming qualities of the boiler seem to be ample. As a vehicle, the engine passes easily around the curves and seems stable and steady; the combination of three coupled axles brought near together with a bogie truck is a good principle. These compound engines appear to satisfy the conditions demanded, to wit: great power for climbing grades combined with a facility for running at high speeds over the easy portions of the line."

Class A3/5 203 (Locobase 2530)

Data from Gustav Reder (Michael Reynolds, trans), The world of steam locomotives (New York: Putnam, 1974), pl 248 and p. 328. See also [], last accessed 19 January 2017, (First viewed August 2002). (Thanks to Ivo Rutishauser for his 24 February 2022 email offering additional information on all of the SBB 4-6-0s and, especially, for clearing up my confusion about which Locobase entry referred to which batch of the class.) Works numbers were 877-878.

Reder wrote that two trial horses (201-202) were built by SLM first. The dimensions were nearly identical, except that the cylinders were testing different compounding layouts. 201 had three cylinders -- HP 458 mm (18.03")/LP 498 mm (19.61") while the 202 used the de Glehn four-cylinder compounding layout in which the HP measure 360 mm (14.17")/LP 548 mm (21.57"). (See Locobases 5955 and 5956).

202's ratio, slightly enlarged, begot the Ten-wheeler design that SLM produced in quantity over the next 12 years.

The design was a success, both on the flat and up the steep Gotthard grades. Travel time between Lucerne and Chiasso dropped to two hours.

[] (August 2002) shows the first 8 production engines (works #1025-1032) as having the dimensions shown above.

10 in the 1898 batch -- works #1123-1132 -- were virtually identical except for 23.23" LP cylinders. Price for all 18 was 106,300 Swiss francs apiece.

According to that same site, these engines managed a max speed in the mountains of 40 kph (25 mph) and 90 kph (56 mph) on the level.

Tonnage ratings were as follows:

Mountain -- freight 140 tons

Mountain -- passenger 140 tons

Level -- freight 600 tons

Level -- passenger 250 tons

10 more locomotives came later. In 1902, 221-224 (works# 1411-1414) carried a boiler of slightly larger size (163.8 sq m/1,762 sq ft) and holding 267 firetubes; these priced at 117,500 SFr each.

See Locobase 10585 for 225-230, produced in 1905.

Class A3/5 225 (Locobase 10585)

Data from "New Locomotive and Train, Gothard [sic] Railway," The Locomotive Magazine, Volume XII [12] (15 September 1906), p. 156. See also Dr. R. Sanzin, "Die Lokomotiven auf der Intertionalen Austellung in Mailand 1906, 17. 3/5 gekuppelte vierzylindrige Verbund-schnellzuglokomotive der oesterischen Staatsbahnen ...", Zeitschrift des Oesterreichischen Ingenieur- und Architeckten-Vereines, Vol LVIII Nr. 51 (21 December 1906), p 715-716. Works numbers were 1659-1664 in 1905.

Beginning with the 1894 batch (Locobase 2530), the Gotthardbahn received 29 de Glehn-du Bousquet four-cylinder compounds.

The last had slightly less heating surface 225-230, produced in 1905 for 109,800 SFr each, reduced the boiler dimensions to 155.8 sq m/1676 sq ft in 227 tubes. One was delivered with the Pielock superheater (see Locobase 13565 for a detailed description of this unit).

Class A3/5 931 (Locobase 5112)

Data from [], last accessed 19 January 2017, (First viewed August 2002). (Thanks to Ivo Rutishauser for his 24 February 2022 email offering additional information on all of the SBB 4-6-0s and, especially, for clearing up my confusion about which Locobase entry referred to which batch of the class.) Maffei works numbers for the first four were 2727-2730. SLM's works numbers for the second half were 1892-1895 in 1908.

These were the last passenger locomotives completed for Gotthard. The basic 3/5 design was superheated with the Clench superheater and enlarged. Cost per locomotive: 146,000 Swiss francs.

According to that same site, these engines managed a max speed in the mountains of 40 kph (25 mph) and 90 kph (56 mph) on the level.

Tonnage ratings were as follows:

Mountain -- freight 150 tons

Mountain -- passenger 150 tons

Level -- freight 560 tons

Level -- passenger 350 tons

(These figures are only slightly better in the mountains than the 1897 SLM engines and worse on the flat. On the other hand, the gotthardbahn site reports, the design proved very economical in steam consumption and thus not coal hogs <>.

As Locobase 4686's description of the Clench superheater comments, its layout only moderately increased steam temperature. Before too long, the SBB replaced the setup with the much more widely used, and effective, Schmidt fire-tube system; see Locobase 20986.

Class A3/5 931-Schmidt (Locobase 20986)

Data from [], last accessed 19 January 2017. See also R Hope, "Lucerne to Chiasso by the Electrified St. Gothard [sic] Railway", Locomotive Magazine, Volume XXX [30], No 388 (24 December 1924), pp. 367-369. (First viewed August 2002). (Thanks to Ivo Rutishauser for his 15 February 2022 email offering additional information on all of the SBB 4-6-0s and, especially, for clearing up my confusion about which Locobase entry referred to which batch of the class.)

Locobase 5112 shows this class as it was delivered with Clench superheaters. The Clench system provided only a modest increase in heating the steam. So the railways replaced the Clench drum, which lay ahead of the front tubesheet and behind the smokebox, with the much more effective Schmidt fire-tube superheater in 1913-1915.

The shops replaced the large bundle of 40 mm fire tubes with many fewer 50 mm tubes, each of which measured 400 mm longer.

Ivo Rutishausen explains the relatively short career of all Gotthardbahn express locomotives. The SBB electrified GB's mainline between Lucerne-Chiasso in 1922, which rendered the 931s redundant.

Because other A 3/5s were better suited to other services, the 931s were scrapped after their retirement in 1925.