Rack railway
A gear train is a rail-based transport network, implement its locomotives the driving force by one or more gears in motion. The fixed engagement of the gear on the mounted on the sleepers between the rails rack allows overcoming stronger gradients than the pure Adhäsionsantrieb whose steel wheels can slip or slide on the steel rails.
Introduction and technology in general
The steel wheel / rail adhesion railways conventional system comes with steep slopes to technical constraints, which are caused by the poor adhesion of the steel wheel on the rail.
- The limit is reached on a dry rail with a gradient of 16 %,
- On a wet track at a gradient of 14 %.
To ensure safe operation, railway lines are generally applied up to 3% slope with up to 7%, on main lines. Exceptions are, for example,
- The German new Cologne-Rhine/Main line with up to 4%
- In France the line Saint- Gervais - Vallorcine with up to 9 %,
- The Pöstlingbergbahn in Linz ( Danube ) with up to 11.6%
- The tram Lisbon with up to 13.5 % slope.
Cog railways overcome as mountain railways gradients of up to 48 % ( Pilatusbahn ) and with only propelled Anspannlokomotiven, also called Treidelloks, up to 50 % ( Panama Canal ).
For rack railways, there are different types of drives that are designed to operational requirements. A distinction between pure cog railways and trains with mixed adhesion and rack drive.
For pure cog railways - usually a few kilometers long cable cars - the drive gear is engaged at all times. The wheels of the locomotives are not driven and can not move without rack. Therefore also the most short flat sections including stations and access roads are fitted to the workshop with racks for pure cog railways.
Mixed trains were built where only individual sections with steep gradients are present. For such paths, the drive vehicles are usually equipped with a combined drive. Occasionally there are separate drives for adhesion and gear. In addition, there were webs in which the Adhäsionstriebwagen were pushed onto the rack sections of Zahnradloks (eg Stanstad -Engelberg -Bahn, Rittnerbahn ). When combined drive adhesion and gear drive are either fixed verkuppelt, or Adhäsionsantrieb can be uncoupled on the rack while driving ( in modern locomotives spread ). For fixed- coupled drive on worn tires can be significant slippage occur. Steam locomotives were built partly as Verbundloks, wherein the low pressure cylinder drive gear, but the Adhäsionsantrieb also helped on the rack route in traction. A modern form of this principle is the differential drive, in which a differential distributes power to Adhäsionsräder and gear.
The advantage of mixed drives is that at flat sections ( when the gear is not engaged ) can be driven at a higher speed. On rack sections is the maximum speed in accordance with Swiss legislation, which usually apply in this area as a reference, limited to 40 km / hr. Downhill apply depending on the inclination and the available braking system lower speed limits.
A special case is the path for the Treidellokomotiven with which the ships are towed through the Panama Canal. In order to increase the traction of locomotives, it was built in the flat sections as a cog railway. The tracks for the empty runs the locos have no rack. The gear drive so moved here the locomotives when towing ( when towing ) on the level sections and the empty trains on the ramps at the locks that have short inclines up to 50%.
Another special case was the Zurich Polybahn up before the rebuild of 1996, when a rack has been used exclusively for the emergency brake, and still in operation Nerobergbahn in Wiesbaden ( water ballast train), in which a rack after the Riggenbach system as a service brake to limit the driving speed and serves as an emergency brake.
Many originally steam-powered trains were electrified later, some steam locomotives were replaced or supplemented by diesel powered vehicles.
Systems
The four world famous rack systems were developed by Swiss and named after them:
- System Riggenbach Niklaus Riggenbach, head rack. Between two U-shaped profiles, the teeth are used as sprouts (originally riveted, welded today ). This design can be combined with simple means finished, but requires custom-made for curves, as the finished rack can not be bent. Soft have therefore as a sliding switch, in which a section of track is shifted performed while today are conventional switches, in conjunction with racks of the system of roll (see below ) are used.
- System Strub Emil Strub, dental splint, exactly one Strub'sche Breitfußschiene involute. The teeth are milled in one of the wedge head rail similar rail. By hooks that grip around the rail head, is to be prevented at particularly steep sections of a Aufklettern, ie the locomotive or a railcar can not be lifted out of the track by the forces on the teeth. Racks by the system Strub can be driven with the same gears as the Riggenbachsche rack, provided pitch and pitch height are equal (eg in the Appenzell Railways ). After the Strubsche rack has not been made 50 years, the company has brought Tensol beginning of the 21st century an improved Strubsche rack on the market that can also be welded continuously in contrast to the precursor.
- Abt system: Carl Roman Abt, slat rack. Two or three blades are offset from each other with the teeth upwards in the track; an appropriate gear engages from above. The particular advantage of using multiple blades is the more uniform power transmission, as always at least one tooth is engaged; this, however, a torsion of the drive gears is required. Technically closely related to the Abt system, the system of Von Roll is with only one blade ( see below). There are for this rack safeguards against a Aufklettern in the form of a track nail, which extends through between two blades and engages its head into the underside of the slats racks. This, however, the racks must be mounted so that the nail for a free clearance is given. Add turnout areas or in shallow sections is laid partly only one lamella ( off-center).
- System Locher: Eduard Locher, herringbone rack. A double rack with teeth on the left and right side lies in the track, the gears engage from the side a. With this system, a Aufklettern is prevented not only by the horizontal force (and thus non hochhebende force), but also by a narrow continuous additional rail behind respectively. under the rack. In addition, the laterally acting forces cancel each other out. The punch system has so far been used only in the Pilatusbahn. The ship lift at the Krasnoyarsk Reservoir uses a similar construction.
In addition, were or are there different species and subspecies ( modified types of common dental systems ) this gear systems:
- System Riggenbach Klose Adolf Klose, head rack. Where the individual teeth between the cheeks resting here on a longitudinal rib, so that the teeth can not twist. This somewhat elaborate system was used only for the electric train to St. Gallen- Gais -Appenzell and on the track Freudenstadt- Baiersbronn the Murgtalbahn
- System Wetli: Kaspar Wetli. The Walzenradsystem should find use in the Wädenswil -Einsiedeln train, did not come due to an accident during a test drive on November 30, 1876 but in commercial operation.
- System Marsh: Sylvester Marsh, head rack with teeth made of round profile. It is used in the built from 1866 and 1869 completed Mount Washington Cog Railway
- System of Roll: Company of Roll ( Today Tensol ), slat rack. Like the Abt system is this rack from a flat steel, in which the teeth are milled with the toothing geometry of the systems Riggenbach and Strub. The rack is primarily for new buildings as well as the replacement of old racks according to the systems Riggenbach or the Strub application because it cheaper and more flexible to use in manufacture than the original production by Riggenbach or Strub. The rack can also be welded continuously.
- Special designs: The Treidellokstrecken of the Panama Canal will be to overcome the differences in height at the locks use special racks, but also based on the Riggenbach system.
Environmental aspects and costs
As all the moving gears also requires a gear train lubrication, typically by fat. This is a loss lubrication, consequently remain on the rack returns the lubricant. This can be washed into the soil by rainfall, for example. To avoid damage to the environment, hence no ordinary machine grease ( petroleum product) may be used but only comparatively expensive - and less temperature resistant - vegetable or animal fats. The consumption of lubricating grease depends on the conditions, a range of several hundred grams per car and mileage is realistic.
History
The invention of the gear drive for railways goes back to the early days of steam locomotives:
Richard Trevithick in 1804 had built the first steam locomotive in the world for the Merthyr Tramroad the Pen-y- Darren ironworks near Merthyr Tydfil in Wales, United Kingdom. This locomotive was too heavy for the cast iron rails, which were designed for towed by horses carriages. Since the rails broke again and again, the operation was discontinued after a few months.
1811 John Blenkinsop was in England the patent number 3431 for his invention, to drive steam engines through gears, who intervened in outside, mounted in parallel to the rail racks. The first cog railway in the world was constructed by him as an industrial railway, leading from the coal mine in Middleton to Leeds in England. It became fully operational on 12 August 1812.
1814 George Stephenson built the locomotive Blücher for the Killingworth colliery, had the steel wheels with wheel flange and scored on steel rails propulsion solely on the principle of Liability / adhesion. This system was up from now on generally by.
American Andrew Cathcart developed Prior to 1847, for the steep section ( six percent) of the Madison & Indianapolis Railroad in the Ohio Valley out a cast iron slats rack and a corresponding locomotive. The railway line was opened in 1848 in operation. 1868, the route was changed with an especially constructed for the purpose locomotive adhesion operation.
The principle of the gear drive was taken up again, as nature has been developed for tourism in the 1860s and railways should climb mountains:
The first mountain railway in the world with gear drive was built in 1866 by Sylvester Marsh. She climbs the Mount Washington, New Hampshire, USA and was opened in 1869.
The after his French patent number 59625 of 1863, designed by Niklaus Riggenbach Vitznau- Rigi Railway was opened in 1871 and is the first mountain railway in Europe with gear drive. It leads from Vitznau to Rigi mountain near Lucerne, Switzerland. Your status as " first cog railway in Europe ", among other things that ( also designed by Riggenbach ) railway was officially opened in the quarry Ostermundigen, despite commissioning in 1870, for marketing reasons only four months after the Rigi.
Oldest active rack railway is put into operation on July 13, 1883 Drachenfelsbahn.
The world's steepest cogwheel railway, with a maximum gradient of 48 percent, opened in 1889, Pilatusbahn near Lucerne in Switzerland. Eduard Locher developed a special, named after him gear system for this course.
List of gear trains
In the mean tracks column
- R = mere cog railway, that is, with toothed rack along the entire length
- G = Mixed adhesion and rack rail, that is, with rack on links
Highlighted in bold are tracks that are still as cog railways in operation
Germany
Austria
Switzerland
Great Britain
Belgium
France
Spain
Portugal
Italy
Greece
Central Eastern Europe
North and Central America
South America
- Sketch