With railways, a break-of-gauge
is where a line of one gauge
meets a line of a different gauge. Trains
and rolling stock
cannot run through without some form of conversion between gauges
, and freight
must otherwise be transloaded
. Either way, a break-of-gauge adds delays, cost and inconvenience to traffic that must pass from one gauge to another.
Transloading of freight from cars of one gauge to cars of another is very labour and time intensive, and increases the risk of damage to goods. If the capacity of freight cars on each system does not match, additional inefficiencies arise. Technical solutions to avoid transloading include variable gauge axles, replacing the trucks of cars, and the use of transporter cars that can carry a car of a different gauge.
Talgo and Construcciones y Auxiliar de Ferrocarriles have developed dual gauge axles (variable gauge axles) which permit through running between broad gauge and standard gauge. In Japan a "Gauge Change Train" has been built on Talgo patents that can run on standard and narrow (1067 mm) gauge.
In some cases, breaks-of-gauge are avoided by installing dual gauge track, either permanently or as part of a changeover process between gauges.
At almost every break-of-gauge, passengers have to change trains, but there are a few passenger trains that runs through a break-of-gauge. For example, the Talgo (variable gauge axles, see above), and the Moscow-Beijing trains (bogie exchange).
For passengers trains the inconvenience is less, especially if it is at a major trains station, where many passengers change trains or end their journey anyway. Therefore some passenger-only railways have been built with other gauge than otherwise in the country, like the high-speed railways in Japan and Spain.
Overcoming a break of gauge
Where trains encounter a different gauge (a break of gauge
), such as at the Spanish-French border or the Russian-Chinese one, the traditional solution has always been transshipment
— transferring passengers and freight to cars on the other system. This is obviously far from optimal, and a number of more efficient schemes have been devised. One common one is to build cars to the smaller of the two systems' loading gauges
that are easily removed and replaced, with a bogie exchange
at an interchange location on the border. This takes a few minutes per car, but is quicker than transshipment. A more modern and sophisticated method is to have multigauge bogies whose wheels can be moved inward and outward
. Normally they are locked in place, but special equipment at the border unlocks the wheels and pushes them inward or outward to the new gauge, relocking the wheels when done. This can be done as the train moves slowly over special equipment.
When transhipping from one gauge to another, chances are that the quantity of rolling stock on each gauge is unbalanced, leading to more idle rolling stock on one gauge than other.
In some cases, breaks of gauge are avoided by installing dual gauge track, either permanently or as part of a changeover process to a single gauge. In other cases (in Spain) variable gauge axles are used.
One method of achieving interoperability between rolling stock
of different gauges, is to piggyback stock of one gauge on special transporter wagons. This enables rolling stock to reach workshops and other lines of the same gauge to which they are not otherwise connected. Piggyback
operation by the trainload occurred as a temporary measure between Port Augusta
during gauge conversion
works in the 1950s, to bypass steep gradients in the Flinders Ranges
Narrow gauge railways were favoured in the underground slate quarries of North Wales, as tunnels could be smaller. The Padarn Railway operated transporter wagons on their gauge railway, each carrying four slate trams. When the Great Western Railway acquired one of the narrow gauge lines in Blaenau Ffestiniog, they used a similar type of transporter wagon in order to use the quarries' existing slate wagons.
Transporter wagons are most commonly used to transport narrow gauge stock over standard gauge lines. More rarely, standard gauge vehicles are carried over narrow gauge tracks using adaptor vehicles; examples include the Rollbocke transporter wagon arrangements in Germany, Austria and the Czech Republic and the milk transporter wagons of the Leek and Manifold Valley Light Railway in England.
The widespread use of containers since the 1960s has made break of gauge less of a problem, since containers are efficiently transferred from one mode to another by suitable large cranes.
Consider the transfer from a train of one gauge to another train of a different gauge. It helps if the lengths of the wagons on each gauge are the same so the containers can be transferred from one train to the other with no transverse movement along the train. The different wagons should carry the same number of containers. Delays to each train depends on how many cranes can operate simultaneously. Clearly the more cranes, the more idle time that they have and the more staff that you need, so this is an economic decision.
Container cranes are relatively portable, so that if the break of gauge transshipment hub changes from time to time, the cranes can be moved around as required. Fork lift trucks can also be used.
There is a gauge transshipment station at Kidatu in Tanzania.
Major breaks of gauge
Major breaks of gauge between large systems include:
- Angola originally had and lines, but the 1,000 mm lines were converted to 1,067 mm in the 1950s in expectation that the lines would meet, but this has never happened.
Democratic Republic of Congo
- DRCongo originally had both and lines, but when these lines met in the 1950s, the line was converted to .
Bangladesh has decided to resolve most of its break-of-gauge problem by converting most of its broad and narrow gauge tracks to dual gauge
(standard gauge) on one hand, Mongolia
(1520 mm) on the other. See the Trans-Manchurian Railway
and Trans-Mongolian Railway
China (standard gauge), Vietnam (metre gauge)
has decided that towns on the narrow gauge system get a second class service, and has decided to convert a significant proportion of the narrow gauge system to broad gauge. This is called Project unigauge
with its standard gauge has break-of-gauge at the borders with Azerbaijan
, and will soon have a new break-of-gauge with Pakistan
. It has a short main line with tracks of Indian broad gauge. Iran has indicated that it would prefer the standard gauge to extend into Pakistan.
While the old national rail network is in narrow gauge , all high speed lines have been built as standard gauge lines. Some lesser towns are served by dual gauge high speed lines. Private railways often use other gauges, but being passenger lines, interchange is not too much of a problem.
The break of gauge occurs on either side of the border river.
in Russia and Mongolia 1520mm in China 1435mm.
Several countries bordering Thailand
use meter gauge track, but there are missing links between Thailand and Vietnam via Cambodia
- France (1,435 mm) and Spain (1,668 mm), for example at Cerbère (FR) - Portbou (ES); Hendaye (FR) - Irun (ES) and Latour-de-Carol.
- Poland, Slovakia, Hungary, Romania (1,435 mm) and former Soviet Union countries: Russia (Kaliningrad), Lithuania, Belarus, Ukraine, Moldova (1,520 mm)
- Finland (1,524 mm) and Sweden (1,435 mm), between Tornio and Haparanda. Railway ferries between Finland and Sweden or Germany (see SeaRail).
- Bulgaria (1,435 mm) railroad ferries to Ukraine, Russia, and Georgia (1,520 mm)
- Switzerland, see "Minor breaks of gauge" section below.
- While breaks of gauge are generally located near borders, a line carrying iron ore from Ukraine extends into Slovakian territory to a steelworks near Košice.
- Queensland and New South Wales ()
- New South Wales (1,435 mm) and Victoria ()
- Southern South Australia uses broad gauge, like Victoria. Northern South Australia had a number of narrow gauge lines, leading to several break-of-gauge stations at various times including Hamley Bridge, Terowie, Peterborough, Gladstone and Port Pirie
- In the latter part of the 20th century, all mainland capital cities were connected by a standard gauge network, leading to more breaks of gauge (or branch line closures) in states where this is not the norm
- Perth's railway system is narrow gauge while the Indian Pacific is standard gauge. The line between East Perth and Midland, the eastern suburban terminus, and inland to the major rail junction at Northam is dual gauge. All rail east of this is standard gauge.
- In May 2008, agreement reached to convert the declining trafficked broad gauge line of a BG/SG pair for 200km between Seymour and Albury to double track Standard gauge for growing interstate traffic.
- Note that the lines of the same gauge do not all join up, being separated by other gauges, deserts or oceans. Rolling stock is often transferred on low-loaders or by ship.
- The United States of America had broad, narrow and standard gauge tracks in the 19th century, but is now almost entirely standard gauge. Similarly the adjacent countries of Canada and Mexico.
- A break-of-gauge, to , between Mexico and Guatemala is currently closed.
Minor breaks of gauge
Wherever there are narrow gauge lines that connect with a standard gauge line, there is technically a break-of-gauge. If the amount of traffic transferred between lines is small, this might be a small inconvenience only. In Austria
there are numerous breaks-of-gauge between standard-gauge main lines and narrow-gauge railways.
The line between Finland and Russia has a minor break-of-gauge. Finnish gauge is 1524 mm and Russian 1520 mm, but this does not stop through-running.
The effects of a minor break-of-gauge can be minimized by placing it at the point where a cargo must be removed from cars anyway. An example of this is the East Broad Top Railroad in the United States of America, which had a coal wash and preparation plant at its break-of-gauge in Mount Union, Pennsylvania. The coal was unloaded from narrow gauge cars of the EBT, and after processing was loaded into standard gauge cars of the Pennsylvania Railroad.
In addition to its broad-gauge lines, Spain has modern high-speed lines operating at standard gauge, and uses gauge converters. These railways are used for passengers only, and they have to change train, usually in big cities where they would have to change train anyway.
While track gauge is the most important factor preventing through running between adjacent systems, other issues can also be a hindrance, including loading gauge
systems, rules and regulations
, and language