Balloon loop

Balloon loop at Linnéplatsen at the tramway in Gothenburg, Sweden.
Double sided island platform on a balloon loop - Olympic Park, Sydney, Australia
P1 & P4 departures
P2 & P3 arrivals
Maules Creek & Boggabri Coal Terminal East balloon loops

A balloon loop, turning loop or reversing loop (North American) allows a rail vehicle or train to reverse direction without having to shunt or even stop. Balloon loops can be useful for passenger trains and unit freight trains such as coal trains.

Balloon loops are common on tram or streetcar systems. Many streetcar and tram systems use single-ended vehicles that have doors on only one side and must be turned at each end of the route, or else haul trailer cars with no driver's cabin in the rear car.


Balloon loops were first introduced on metro and tram lines. They did not appear on freight railways in large numbers until the 1960s when the modernising British Rail introduced merry-go-round (MGR) coal trains that operated from mines to power stations and back again without shunting.


Balloon loops enable higher line capacity (faster turnaround of a larger number of trams) and also allow the use of single-ended trams which have several advantages, including lower cost and more seating when doors are on one side only. However, double-ended trams also benefit from the capacity advantage of balloon loops, for example on the former Sydney tram system where loops were used from 1881 until the system's closure in 1961. Initially the Sydney system was operated by single-ended steam trams and then, from the 1890s, by double-ended electric trams. Lines were looped in the Sydney CBD and the other busiest areas of operation, such as the La Perouse, New South Wales and other eastern suburbs lines, as they provided greater turn-around capacity on this very busy system. The Sydney system was possibly the first major example of a looped tramway system. European systems were extensively converted to looped operation in the early twentieth century and most of them changed to single-ended trams. Looped operation with single-ended trams was also used on many North American streetcar systems.



South Ferry balloon loop

On a balloon loop: the station is on the balloon loop, and the platform may be curved or straight.



United States

Lower level (suburban) layout of the Grand Central Terminal, showing a balloon loop
Upper level (mainline) layout of the Grand Central Terminal, showing a balloon loop

United Kingdom

Simplified rail network around Newcastle
East Coast Main Line via Morpeth
Heaton Depot
North Tyneside Loop via Walkergate
Heaton Closed 1980
Riverside Branch via Byker
North Tyneside Loop via Jesmond
Manors Tyne and Wear Metro
Carliol Square
Closed 1850
Tyne Valley Line via Scotswood  
Newcastle Central Tyne and Wear Metro
King Edward VII Bridge 
High Level Bridge River Tyne

Tyne Valley Line via Metrocentre 
Durham Coast Line via Heworth
East Coast Main Line via Durham 


Multiple stations on a balloon loop:

With balloon loop: The balloon loop is past the station.

Brooklyn Bridge and City Hall stations in New York City.

Paris Métro

Tram Systems

Balloon loops are used extensively on tramway systems with single-ended trams. Usually located at termini, the loop may be a single one-way track round a block. Single-ended trams have a cab at only one end and doors on one side, making them cheaper and having more space for passengers. On tram systems with double-ended trams balloon loops are not required but may still be used as they can provide greater turn-around capacity than a stub terminus; the Birmingham Corporation Tramways terminus at Rednal had a balloon loop in addition to the conventional stub tracks, providing extra capacity to handle weekend and bank holiday crowds visiting the nearby Lickey Hills. The Milan interurban tramway network, although using double-ended trams, had balloon loops at termini within the city limits so that they could be used as backup termini by the single directional trams used on urban service. In Milan, tramway depots are built as balloon loops, just as urban termini. Another example is in Potsdam, Germany.




Loading loops

New South Wales
South Australia
Western Australia

Unloading loops

New South Wales
South Australia
West Australia



New Zealand

United Kingdom

There are several balloon loops at power stations in the UK; these have been provided so that coal trains may unload without stopping (known as the merry-go-round system). Examples include Cottam, Didcot, Drax, Eggborough, Ferrybridge, and Ratcliffe-on-Soar.

Also, the Fife Circle line between Edinburgh and the county of Fife acts like a giant balloon loop, branching off after Inverkeithing and connecting again at Kirkcaldy.

United States


Both the French and the British terminals of the Eurotunnel Shuttle service through the Channel Tunnel consist of balloon loops.

Occasionally, balloon loops are used for reversing trains on lines with heavy grades and tight curves to equalise wear on both sides of locomotives and rollingstock. Such a balloon loop was constructed at Beech Forest on the 2 ft 6 in (762 mm) Victorian Railways line from Colac to Crowes.


Advantages of a balloon loop include:

Compared to stations with stub platforms, balloon loops allow:


The major disadvantage is that a balloon loop is very space consuming. Another disadvantage is that the sharp curves cause noise, as well as wear on wheels and rails. Also, if the platform is located on the curve, the gap between the platform and railcar door is a hazard. The former South Ferry station on the New York City Subway solved this problem by using gap fillers that extended out to the railcar door when the train triggered a switch on the tracks. The older station had been closed, but was reopened as a result of damage to the newer station caused by Hurricane Sandy.

On systems where, for reasons of economy, the couplings are made non-reversible (e.g. by fitting the air brake pipe along one side of the car only), the use of a reversing loop will cause a proportion of the rolling stock to face the "wrong" way and it may not be possible to assemble a complete train in a depot, even if sufficient cars are on hand. This was the case on the Charing Cross, Euston and Hampstead Railway (now part of the Northern line of London Underground). After the opening of a loop at Charing Cross (Embankment) in 1914 (replaced in 1926 by the present Kennington loop) car ends were marked "A" or "B" (later, when axles were designated by letters, the "B" car ends became "D" to match the adjacent axle), and it was not permitted to couple cars together if the ends to be coupled bore the same letter. It was found necessary to provide a turntable at Golders Green depot (near the other end of the line), for use when there was an imbalance of car directions.[21]

To avoid this problem, on many systems with a balloon loop the couplings and brake hoses are made reversible.

At coal ports such as Kooragang in Newcastle, New South Wales the space inside the balloon loops is used for storing coal, so that it is not wasted.

At the Olympic Park station in Sydney, the loop is flattened where the platforms are located, so that the platform faces are straight.

Wikimedia Commons has media related to Rail track loops.


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  18. Railway Digest Oct 2014, pg38
  19. Railway Digest Oct 2014, pg38
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