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A 'Balloon loop' is a track arrangement that allows a train to reverse direction, and return to where it came from, without having to shunt or even to stop.

Contents

Use

Examples

Passenger

★ Non-passenger loops: Porte Dauphine (line 2), Porte de Lilas (line 3bis), Porte de Clignancourt and Porte d'Orléans (line 4) ★ Passenger loops: Nation (line 2), Charles de Gaulle-Etoile and Nation (line 6), Pré-Saint-Gervais (line 7bis) ★ The western end of line 10 deserves a special mention, as it is long loop: trains arriving at Mirabeau from Gare d'Austerlitz enter a loop with a few stations on it: Eglise d'Auteuil, Auteuil, Porte d'Auteuil (official terminus), Miche-Ange Molitor, Chardon Lagache and Mirabeau again, to continue eastwards ★ There also are a few loops used for stabling trains, for example west of Invalides and north of Porte de la Villette.

Freight

New South Wales, Australia

Other

History

Disadvantages

Advantages

Other Olympic stations

See also

Use

Balloon loops can be useful for passenger trains, and ''unit'' freight trains, such as coal trains.
Balloon loops do not include track layouts where combinations of junctions allow a train reversal, where this reversal is not regularly used.
In some transport simulators (eg: Transport Tycoon Deluxe, 1996 but still played worldwide), Balloon Loops are referred to as RoRo stations or Roll On, Roll Out. They are frequently used at busy stations.

Examples

Passenger

★ Olympic Park, Sydney, Australia Platforms 1 and 4 are for boarding; platforms 2 and 3 are for alighting.

★ City Hall, New York City. USA: One platform for both boarding and alighting (now closed)

★ South Ferry, New York City: Two tracks, two platforms (one closed)

★ Schwabstrasse Stuttgart S-Bahn, Loop is south of the station and completely underground

★ Bad Herrenalb, Albtalbahn, Germany: Train passes loop before arrival

★ Dungeness railway station, Romney, Hythe & Dymchurch Railway, Kent, England. Single track, single platform for both boarding and alighting.

★ Kennington tube station, on the London Underground Northern Line, trains from the Charing Cross branch can terminate at Kennington and then run around a loop to return north. Due to the layout, trains from the Bank branch may not access this loop.
=== Paris Métro

★ Non-passenger loops: Porte Dauphine (line 2), Porte de Lilas (line 3bis), Porte de Clignancourt and Porte d'Orléans (line 4)

★ Passenger loops: Nation (line 2), Charles de Gaulle-Etoile and Nation (line 6), Pré-Saint-Gervais (line 7bis)

★ The western end of line 10 deserves a special mention, as it is long loop: trains arriving at Mirabeau from Gare d'Austerlitz enter a loop with a few stations on it: Eglise d'Auteuil, Auteuil, Porte d'Auteuil (official terminus), Miche-Ange Molitor, Chardon Lagache and Mirabeau again, to continue eastwards

★ There also are a few loops used for stabling trains, for example west of Invalides and north of Porte de la Villette.

Tram Systems ===
Balloon loops are used extensively on a majority of tram systems, usually at the terminal stations.¨Sometimes such a loop is actually a single one-way track round a block. These loops allow use of trams with a cab at only one end and doors on one side (like a bus). Such trams are cheaper and have more space for passengers. Other tram systems have trams constructed like normal trains, with a cab at both ends and doors on both sides, so they can be used in either direction.

Freight

New South Wales, Australia

★ Newnes Junction coal loader -

★ Mount Thorley - coal

★ Camberwell - coal

★ Ulan - coal

★ Penny Road, near Moree - wheat

★ Fassifern - has triangle as well, so trains can go north or south.

★ Vales Point

★ Newdell Junction - has two balloon loops.

★ Bargo - due to change in operational requirements, the balloon loop now points the wrong way, and requires trains to be top and tailed!

Other

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

History

Balloon loops first appeared on railways in large numbers in the 1960s when the modernising British Rail introduced so-called ''merry-go-round'' coal trains that operated without shunting from mines to power stations and back again, around the clock. This track arrangement was introduced on metro and tram lines much earlier.

Disadvantages

The only real disadvantage of a balloon loop is that it needs a lot of space to build, and even so, the curves can be very sharp. The very sharp 180 m radius curves on the Olympic Park balloon loop cause noise, wear and tear on both the wheels and rails. Any platforms should be located on straight track, since if they are located on curved track, the gap between platform and carriage door can be a hazard.

Advantages

The advantages of a balloon loop include -

★ smooth operation.

★ trains can arrive in any free platform, while another train is leaving any platform.
If Olympic Park station were not on a balloon loop and were a stub platform:

★ more tracks and platforms would be required.

★ arrivals into some platforms could block departures from other platforms.

★ time would be lost while drivers change ends and reset the train for the other direction.

★ if the driver changed ends and discovered a hidden fault, then delays to trains would be likely.

Other Olympic stations

★ The Olympic station at Berlin, Germany has two through platforms and about 8 turnback platforms. This is considerably more than the 2 track / 4 platform arrangement at Sydney.

See also

★ Railway station layouts

★ Island platform

★ Side platform