SNCF 2-12-0 Locomotives in France

Class 160A (Locobase 2130)

Data from Thierry Stora, "2 12 0 prototype" on his long-lived French Compound Locomotive Webpage at [] (first accessed in 2002 and most recently 16 February 2024; and Raymond Gleize, "60 A 1 : La machine à monter après les murs" on the Del.Gleize.net website at []; "DH", "Locomotive 160 A 1 prototype by André Chapelon" posted 28 May 2022 on the Cheminot Transport blog at []; "L'âge Chapelon : excellence de la vapeur française" on the trainconsultant website at []. (Thanks to Alexander Blessing for his 4 February 2024 email noting the valve gear.)

This Chapelon rebuild took a 2-10-0, added an axle and two cylinders, and created one of the heaviest locomotives built in Europe.

Thierry Stora says that the design sought to maximize steam production at low speeds. Chapelon explored the idea of a triple-expansion design using a Franco-Crosti boiler and one HP, one MP, and two LP cylinders. As the design worked best at 40 atmospheres (572 psi) and Chapelon had to use a standard boiler, he tried a different approach. Inside the frames he located two HP cylinders driving the fourth driver set and two LP cylinders of the same 520 mm diameter to drive the second set. He positioned two larger LP cylinders (640 mm) outside to drive on the third axle. For the six cylinders, Chapelon had two independent sets of valve gear.

The boiler was divided into two sections, with the front two meters (78 3/4") housing the pre-heater. A Houlet superheater with 72 sq m ( 775 sq ft) of surface served the HP cylinders while a modified Schmidt Type A (110.46 sq m/1,189 sq ft) supported the LP cylinders. According to Stora, the Schimdt four-element heater was actually laid out as two parallel sets of two series circuits.

Its Belpaire firebox was barely visible behind the boiler and in front of the cab. Over the smokebox, Chapelon's double Kychap exhaust system contributed to efficiency.

Over a series of 17 trials in 1948, the 160.A1 showed enough power to haul the maximum allowed tonnages on four different routes without any helper engines.. The four sections were:

1650 tonnes between Laroche and Dijon.

1000 tonnes between Roanne and Saint-Etienne.

850 tonnes between Badan and Saint-Etienne-Pont de l'Ane.

550 tonnes between Lyon and Roanne via Tarare.

Calculated tractive effort in compound was 83,700 lb (37,966 kg) with coal consumption rates of 1.87 lb [0.85 kg]/hp/hr and water 18.72 lb [8.49 kg]/hp/hr.