Underfriction

On a roller coaster train, the underfriction, up-lift, or up-stop wheels are a device to keep the train from jumping off the track under intense movement.^[1] The design was patented in 1919 by John A. Miller.^[2]^[3]

References

^ Witter, Bret (2003). Carnival Undercover. Plume. p. 113. ISBN 978-0-452-28428-9.
^ Pleasure railway structure
^ Cartmell, Robert (1987). The Incredible Scream Machine: A History of the Roller Coaster. Popular Press. p. 117. ISBN 978-0-87972-342-2.

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[1] Witter, Bret (2003). Carnival Undercover. Plume. p. 113. ISBN 978-0-452-28428-9.

[2] Pleasure railway structure

[3] Cartmell, Robert (1987). The Incredible Scream Machine: A History of the Roller Coaster. Popular Press. p. 117. ISBN 978-0-87972-342-2.

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