{{Short description|Practice of carrying truck semi-trailers on railroad freight cars}} [[File:Spine car 02.jpg|thumb|Spine cars with semi trailers on them]] '''Trailer-on-flatcar''', also known as '''TOFC''' or '''piggyback''', is the practice of carrying semi-trailers on railroad flatcars. TOFC allows for shippers to move truckloads long distances more cheaply than can be done by having each trailer towed by a truck, since one train can carry more than 100 trailers at once.<ref name=":0">{{Cite book|last=Schafer|first=Mike|title=Freight train cars|date=1999|publisher=MBI Pub|others=Mike McBride|isbn=0-7603-0612-5|location=Osceola, Wis.|pages=20–21, 29|oclc=41002704}}</ref> The trailers will be moved by truck from their origin to an intermodal facility, where they will then be loaded onto a train, typically by a rubber tired gantry crane, for the bulk of their journey. Alternatively, trailers may be driven onto the flatcars via ramps by a terminal tractor. Near the destination, the trailers are unloaded at another facility and brought to their final destination by a tractor unit.<ref name=":1">{{Cite book|last=Ayre|first=Josephine|url=https://books.google.com/books?id=GaceAQAAMAAJ|title=History and Regulation of Trailer-on-flatcar Movement (piggyback)|publisher=U.S. Bureau of Public Roads|year=1966|archive-date=2021-09-26|access-date=2021-09-26|archive-url=https://web.archive.org/web/20210926005240/https://books.google.com/books?id=GaceAQAAMAAJ|url-status=live}}</ref>
Modern TOFC service was introduced in North America in the 1950s, although the practice of carrying another mode of transport on flatcars was first recorded in 1843 when canal boats were moved by a portage railway between several cities in Pennsylvania.<ref name=":0" /><ref name=":1" />
TOFC is distinct from containerization. While both are examples of intermodal transport, trailer on flatcar is the loading of entire trailers onto railroad cars, while in containerization, the container is detached from the trailer chassis for railroad transport.
== Gallery ==
<gallery mode="packed" caption="Trailers on flatcar" heights="160px"> File:Santa_Fe_TOFC_(Trailer_on_Flat_Car)_(10589289363).jpg|A Santa Fe semi-trailer carried on a flatcar as part of a TOFC train. File:Union Pacific first trailers on flatcars from Denver 1955.JPG|Semi-trailer on flatcar service run by the Union Pacific Railroad in 1955 File:Trailer On Flat Car, Southern (10589062626).jpg|A semi-trailer on a flatcar of the Southern Railway File:89 foot flat car intermodal.png|Four {{convert|89|ft|m|2|adj=on}} long intermodal flatcars Image:Flat car - KCS 8985.jpg|This Kansas City Southern Railway flatcar is fitted with fifth wheel couplings for hauling trailers. (2004) </gallery>
== Infrastructure requirements== thumb|Adequate AAR loading gauge for TOFC Besides the need for facilities to handle loading and unloading with road (preferably highway) access, trailer on flatcar operations impose certain height clearance requirements. In North America, including Mexico, this is mostly a non-issue as double-stack rail transport imposes much more demanding clearance requirements,<ref>{{Cite web |url=https://my.aar.org/OTLR/Documents/Section%201/Section1AppendixA_20200826.pdf |title=AAR clearance outlines |access-date=2021-11-13 |archive-date=2021-02-24 |archive-url=https://web.archive.org/web/20210224215901/https://my.aar.org/OTLR/Documents/Section%201/Section1AppendixA_20200826.pdf |url-status=dead }}</ref> but regions with more constrained loading gauges may impose limits on this type of transport or make it impossible altogether. However, height clearance requirements tend to be slightly lower than for rolling highway transportation where entire trucks are loaded onto rail vehicles. The trailers themselves also need to meet certain minimum requirements to be able to be moved via crane, which is the most cost- and time-efficient way of loading and unloading them onto the train.<ref>{{Cite news |last=Jentsch |first=Bernd |date=November 5, 2021 |title=Thüringen als Verkehrsdrehscheibe in Europa |language=de |trans-title=Thuringia as a transport hub in Europe |work=Ostthüringer Zeitung |url=https://www.otz.de/thueringen-als-verkehrsdrehscheibe-in-europa-id233753941.html |access-date=November 12, 2021}}</ref><ref>{{Cite web |last=Nallinger |first=Carsten |date=September 30, 2014 |title=Kranbare Lösungen sind gefragt |trans-title=Crane solutions are in demand |url=https://www.eurotransport.de/artikel/kombinierter-verkehr-kranbare-loesungen-sind-gefragt-6575013.html |access-date=November 12, 2021 |website=Eurotransport |language=de |archive-date=November 12, 2021 |archive-url=https://web.archive.org/web/20211112115859/https://www.eurotransport.de/artikel/kombinierter-verkehr-kranbare-loesungen-sind-gefragt-6575013.html |url-status=live }}</ref> To allow trailer on flatcar transport involving maximum height trailers, Switzerland is upgrading existing lines feeding into the "Gotthard Axis" of the New Railway Link through the Alps to a so-called "4-m corridor" named for the {{convert|4|m|ft|sp=us}} maximum height of the trailers as specified in road transport regulations.<ref>{{Cite web |title=4-Meter-Korridor |trans-title=4-Meter Corridor |url=https://www.bav.admin.ch/bav/de/home/verkehrstraeger/eisenbahn/bahninfrastruktur/ausbauprogramme/weitere-ausbauprogramme/4-meter-korridor.html |access-date=November 12, 2021 |website=Bundesamt für Verkehr |language=de |archive-date=November 12, 2021 |archive-url=https://web.archive.org/web/20211112120445/https://www.bav.admin.ch/bav/de/home/verkehrstraeger/eisenbahn/bahninfrastruktur/ausbauprogramme/weitere-ausbauprogramme/4-meter-korridor.html |url-status=live }}</ref> As upgrading the loading gauge of an existing railway can be very expensive, especially when tunnels and bridges follow in close succession like on the right Pegnitz Valley line,<ref>{{Cite web |title=Die Bahnbrücken in Nordostbayern |trans-title=The railway bridges in Northeast Bavaria |url=https://www.bahnausbau-nordostbayern.de/eisenbahnbruecken.html |access-date=November 12, 2021 |website=Bahnausbau Nordostbayern |language=de}}</ref><ref>{{Cite web |title=Die Eisenbahntunnel in Nordostbayern |trans-title=The railway tunnel in Northeast Bavaria |url=https://www.bahnausbau-nordostbayern.de/tunnel.html |access-date=November 12, 2021 |website=Bahnausbau Nordostbayern |language=de |archive-date=November 12, 2021 |archive-url=https://web.archive.org/web/20211112121547/https://www.bahnausbau-nordostbayern.de/tunnel.html |url-status=live }}</ref> increasingly newly built lines are built to the most generous standards deemed feasible, even if the need for such generous clearances seems remote at the time of construction. For example, the Betuweroute in the Netherlands an important freight link from the Dutch seaports to the Blue Banana had all bridges and tunnels built to standards allowing double stack rail transport in the future by simply raising the overhead wire.<ref>{{Cite web |last=Worsford |first=Frank |date=April 1, 2004 |title=The Betuweroute solution |url=https://www.logisticsmanager.com/3493-the-betuweroute-solution/ |access-date=November 12, 2021 |website=Logistics Manager}}</ref><ref>{{Cite web |title=Betuweroute Double-Track Freight Line |url=https://www.railway-technology.com/projects/betuweroute/ |access-date=November 12, 2021 |website=Railway Technology}}</ref>
== See also == * Kangourou wagon * Modalohr * Pocket wagon * Rolling highway - a similar practice, but transporting complete semi-trailer trucks. * Roadrailer
== References == {{Reflist}}
Category:Intermodal transport Category:Freight rolling stock Category:Trailers