Grand union

This article is about a type of tram/streetcar/railway junction. For other uses, see Grand union (disambiguation).
Track arrangement of a street railway Grand Union.

A grand union is a rail track junction where two double-track railway lines cross at grade, often in a street intersection or crossroads. A total of sixteen railroad switches (sets of points) allow streetcars (or in more rare installations, trains) coming from any direction to take any of the three other directions. The same effect may be achieved with two consequent wyes if the location allows for space.

Complexity

These types of complex junction are expensive to build and expensive to maintain. Special parts, sometimes made of manganese steel, are needed for each location where one rail crossed another (a "frog"); these parts often need to be custom-made and fitted for each single location, depending on the specific angle of crossing of the intersecting streets.

A full grand union junction consists of 88 frogs (where one rail crosses another rail), and 32 switchpoints (point blades) if single-point switches are not used. A tram or train crossing the junction will encounter four or twenty frogs within the space of crossing the junction.

For all of the possible tracks of a grand union to be used during normal operation, at least six different tram routes have to cross the union. In an intersection with lines oriented towards cardinal directions, these could be: north-south, north-east, north-west, south-east, south-west, and east-west.

Three-Quarter, Half, and Butterfly Unions

Chicago Transit Authority control tower 18 at this three-quarter union guides elevated Chicago 'L' north and southbound Purple and Brown lines intersecting with east and westbound Pink and Green lines and the looping Orange line above the Wells and Lake street intersection in the loop.

Three-quarter unions are similar to grand unions in that they are also rail track junctions where two double-track railway lines cross at grade, often in a street intersection or crossroads; the primary difference being that one corner of the crossing does not have curved junction tracks, with the union having a total of twelve railroad switches (sets of points).

Half unions are similar, but only have curved junction tracks on two adjoining corners of the intersection, with a total of eight switches/points.

Butterfly unions share the total of eight switches/points, but the curved junction tracks are on opposing corners.

Examples


Americas

Canada

USA

Australasia

Europe

Austria

Czech Republic

Germany

Italy

Netherlands

Poland

Russia

Slovakia

Switzerland

United Kingdom

See also

Wikimedia Commons has media related to Grand unions.

References

  1. Edmonton Radial Railway 1924 track map Archived July 6, 2011, at the Wayback Machine.
  2. "Edmonton Radial Railway Society photograph, 109th St. and Jasper Ave., 1904". Edmonton-radial-railway.ab.ca. Retrieved 2013-01-07.
  3. "Musée McCord Museum photograph - Tramway crossing under construction, 1893". Mccord-museum.qc.ca. Retrieved 2013-01-07.
  4. http://transit.toronto.on.ca/archives/maps/cars06.pdf
  5. www.Chicago-L.org Photo "tower18l.jpg" taken June 19, 2006.(Retrieved November 2009)
  6. "Original PRT specialwork drawing sheet 10, chart 48". Phillytrolley.org. 1919-06-30. Retrieved 2013-01-07.
  7. "PTC Track Map detail, 1954, bottom right corner of image". Phillytrolley.org. Retrieved 2013-01-07.
  8. "Original PRT specialwork drawing sheet 16, chart 66". Phillytrolley.org. 1919-06-30. Retrieved 2013-01-07.
  9. "PTC Track Map detail, 1954, center left of image". Phillytrolley.org. Retrieved 2013-01-07.
  10. "PTC Track Map detail, 1954, center left of image". Phillytrolley.org. Retrieved 2013-01-07.
  11. "Map of Rochester Subway, see inset section for surface track layout". Rocwiki.org. 2005-03-20. Retrieved 2013-01-07.
  12. "Powers Building photograph, Rochester NY, 1904". Shorpy.com. Retrieved 2013-01-07.
  13. http://pauldorpat.com/wp-content/uploads/2010/09/Waiting-for-8-14-23-THENWEB.jpg
  14. Graham Stewart, The End of the Penny Section: When Trams Ruled the Streets of New Zealand, rev ed. (Wellington: Grantham House, 1993), p. 149.
  15. "Victorian Heritage Database: photographs and diagram of junction". Vhd.heritage.vic.gov.au. Retrieved 2013-01-07.
  16. Google Maps: 217 Balaclava Rd, Caulfield North VIC 3161, Australia
  17. Google Maps: Jugoslávská 18 613 00 Brno-sever, Czech Republic
  18. Google Maps: Palackého 621/1 779 00 Olomouc, Czech Republic
  19. Google Maps: Zenklova 180 00 Praha 8, Česká republika
  20. Google Maps: Strossmayerovo náměstí 976/1 170 00 Praha 7-Holešovice, Czech Republic
  21. Gleisplan der Straßenbahn Cottbus
  22. Google Maps: Karlstraße 63 76137 Karlsruhe, Germany
  23. Google Maps: Untere Königsstraße 60 34117 Kassel, Germany
  24. Google Maps: Maximilianstraße 47 80538 München, Germany
  25. Google Maps: Piazza 24 Maggio, Milano Italy
  26. Google Maps: Piazzale Porta Lododica, Milano Italy
  27. Google Maps: Piazza della Repubblica, Milano Italy
  28. Google Maps: Van Woustraat 83III 1074 Amsterdam, The Netherlands
  29. Google Maps: Eerste Constantijn Huygensstraat 98 1054 Amsterdam, The Netherlands
  30. Google Maps: Jan Evertsenstraat 144II 1056 Amsterdam, The Netherlands
  31. Google Maps: Ceintuurbaan 55-157 1072 Amsterdam, The Netherlands
  32. see Sporenplan.nl
  33. Google Maps: Vasteland - Westzeedijk Rotterdam, The Netherlands
  34. Google Maps: Franklina Roosevelta 11, Poznań, Poland
  35. Google Maps: Rondo Kaponiera, Poznań, Poland
  36. Google Maps: Rondo Jana Nowaka-Jeziorańskiego, Poznań, Poland
  37. Google Maps: Hetmańska 57, Poznań, Poland
  38. Google Maps: E261 Poznań, Poland
  39. Google Maps: E261 Poznań, Poland
  40. Google Maps: 629 Warszawa, Poland
  41. Google Maps: Rondo Kercelak, Warszawa, Poland
  42. Google Maps: Rondo Zgrupowania AK "Radosław", Warszawa, Poland
  43. Google Maps: 55.780459 N, 49.112853 E
  44. Google Maps: Preobrazhenskaya Ploshad, Moscow Russia
  45. Google Maps: Aeschenplatz 1 4052 Basel, Switzerland
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