List of railroad truck parts

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A diagram of an American-style truck showing the names of its parts

A bogie or railroad truck holds the wheel sets of a rail vehicle.


Also called an axle box, or journal box in North America,[1] an axlebox is the truck or bogie assembly that houses the end of the axle. Early axleboxes contained friction bearings in which the axle spun in a bed of oil. Friction bearings are now illegal in interchange service in the United States; modern axleboxes use roller bearings.[2][3] As early as 1908 they contained a set of long cylindrical rollers allowing the axle to rotate.[4][5] It was also used on steam locomotives such as the Victorian Railways A2 class, the LMS Garratt, the LSWR 415 class, and the GCR Class 1.[4][dubious ]

Center pin[edit]

A large steel pin—or rod—which passes through the center plates on the body bolster and truck bolster.[6] The truck turns about the bolt, and stress is taken by the center plates.[6]

Center plate[edit]

One of a pair of plates which fit one into the other and support the car body on the trucks allowing them to turn freely under the car.[6] The one on the truck may also be called center bowl.[7]

Truck side frame[edit]

The frame at either side of the truck.[2][3]

Truck bolster[edit]

Each truck has a bolster—a transverse floating beam—between the side frames.[8] It is the central part of every truck on which the underframe of the railcar or railroad car is pivoted through the center pivot pin.[6][8]

Image gallery[edit]

A journal box 
This Bettendorf-style freight car truck uses journal bearings in journal boxes. The center pin can be seen pointing up from the bolster. 
Railroad car wheels are affixed to a straight axle, such that both wheels rotate in unison. This is called a wheelset
An archbar-type truck with journal boxes 
A Bettendorf-style truck with axle boxes at the wheels 
Japanese archbar truck with axleboxes at the wheels 

See also[edit]


  1. ^ "Railroad Dictionary: J". CSX Corporation. 2012. Archived from the original on 29 July 2014. Retrieved 15 November 2014. 
  2. ^ a b "AAR M-1003 Certified Truck Component Manufacturing". Columbus, Ohio: Columbus Castings. Retrieved 19 November 2014. 
  3. ^ a b "General Information" (PDF). Standard Car Truck Company. January 2000. Archived from the original (PDF) on 4 March 2016. Retrieved 19 November 2014.  |section= ignored (help)
  4. ^ a b "The Evolution of Railway Axlebox Technology". Evolution. SKF. 7 December 2010. Retrieved 18 September 2014. 
  5. ^ "Glossary: A". Railway Technical Web Pages. 2014. Archived from the original on 7 October 2014. Retrieved 19 November 2014. 
  6. ^ a b c d "Railroad Dictionary: C". CSX Corporation. 2012. Archived from the original on 1 April 2015. Retrieved 15 November 2014. 
  7. ^ "APTA PR-CS-RP-003-98 Recommended Practice for Developing a Clearance Diagram for Passenger Equipment" (PDF). American Public Transportation Association. 26 March 1998. Retrieved 17 January 2015. 
  8. ^ a b "Railroad Dictionary: B". CSX Corporation. 2012. Archived from the original on 29 July 2014. Retrieved 15 November 2014. 

Further reading[edit]