Fell locomotive

NZR H 199 in the Fell Engine Museum, Featherston, New Zealand

Underside of the locomotive with the friction wheel drive and caliper brake

The Fell locomotive is a type of locomotive in which additional friction wheels increase the tractive force that can be transmitted.

function

Starting position

In rail operations, with wheel-rail technology, the friction between the rail wheel and rail is low, as both components are made of steel . Therefore, the slope that vehicles of a conventional adhesive track can travel is limited. In order to increase it, efforts were made early on to increase the friction of the wheel-rail system:

• "Sanding" is only suitable as an auxiliary measure when starting up and on short sections (in this case, sand is scattered on the rails in front of the driven wheels to increase friction).
• The use of racks is used in rack railways , but this technology limits the possible travel speed, especially at the rack entrances and exits. At the same time, they are subject to heavy wear.

Fell technique

Cross-section of a track with a fur middle rail

Fell locomotives solve the problem with a center rail friction wheel drive. A third rail is raised in the middle of the track. This center rail ("double head rail") is surrounded on both sides by additional drive wheels lying horizontally on the underside of the locomotive . Springs or steam pressure press these drive wheels against the rail and thus increase the friction. The friction wheels are driven by their own steam cylinders, the contact pressure being variably set by the driver using a spindle. This middle rail can serve as an additional braking device on slopes, also for cars that are equipped accordingly. The elevated position of the middle rail enabled unrestricted access to control points.

history

Emergence

The design was originally developed by Georg Escol Sellers in 1847 . However, it was only successful through the work of the British John Barraclough Fell , whose name it bears today. The principle is not only applicable to steam locomotives , but no locomotives of other types of traction were equipped with a Fell drive.

Former railways

France

This technique was used for the first time in France between 1868 and 1871 to cross the Alps over the Mont-Cenis- Pass from Lanslebourg to Susa . This line only ran for three years until the Mont Cenis tunnel was completed. The route had gradients of up to 85 ‰ on the French side and up to 80 ‰ on the Italian side.

Until 1926, a Fell Railway also ran in France from Clermont-Ferrand to Puy de Dome . The locomotives were equipped with an improved drive by engineer Hanscotte , in which the friction wheels were pressed against the center rail by means of compressed air cylinders. A rack railway has been running on the same route since 2012 (see Panoramique des Dômes ).

The central rail on the St-Gervais-Le Fayet-Chamonix-Vallorcine line in France was used exclusively for braking . Because of the all-axle drive, it was only used for emergency braking. After the PLM railcars from the early days were taken out of service and vehicles with magnetic rail brakes were used , it was unnecessary and was expanded. The brake rail required a particularly high installation position of the gear drives and thus the racks on the Swiss connecting route Martigny – Châtelard , which has been retained to this day.

New Zealand

The Fell system was only widely used in New Zealand , where it was used on three routes and as a braking system for cable cars and light railways. Of the Fell locomotives formerly used on the Rimutaka route in the province of Wairarapa on New Zealand's North Island , only one has been preserved and is in the “ Fell Engine Museum ” in Featherston . For the planned reconstruction of this railway as a tourist and museum railway , the construction of two new Fell locomotives is also planned.

Operated system

Since the system is complicated and rack railways were ultimately more efficient, Fell locomotives were rarely used. Today only the Snaefell Mountain Railway on the Isle of Man regularly uses a skin center rail, but only for braking with caliper brakes during the descent.

Overview of the routes with the Fell technique

France

• Chemin de Fer du Mont Cenis from 1868 to 1871 (this railway was intended as a temporary solution until the opening of the Mont Cenis tunnel)
• Chemin de fer du Puy-de-Dôme from 1907 to 1926
• Saint-Gervais – Vallorcine route

New Zealand

• Rimutaka Incline from 1878 to 1955;
• Roa Incline from 1909 to 1966
• Rewanui Incline from 1914 to 1965

Brazil

• Linha de Cantagalo Niterói – Nova Friburgo until 1964, when the fur rail was used, remains unclear

literature

• PJG Ransom: Narrow Gauge Steam - It's origins and worldwide development . Oxford Publishing 1996. ISBN 0-86093-533-7
• The Mont Cenis Railway and Tunnel . In: Harper's new monthly magazine (July 1871).

See also

• The magnetic rail brake works independently of the vehicle weight (more precisely: the friction mass ) and wheels.

Individual evidence

1. ↑ Röll (1912), Dreischienenbahnen , pp. 441–442
2. ↑ see also fr: Jules Hanscotte in the French-language Wikipedia
3. ^ Rimutaka Incline Railway. Stage 3 - Summit to Cross Creek ( Memento of the original from September 21, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
4. ↑ [1]