A Cartazzi axle is a design of

leading In typography, leading ( ) is the space between adjacent lines of type; the exact definition varies. In hand typesetting, leading is the thin strips of lead (or aluminium) that were inserted between lines of type in the composing stick to incre ...

trailing wheel On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle (Wheelset (rail transport), wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing Bogie, t ...

support used worldwide. The design was used extensively on the former LNER's Pacific steam locomotives and named after its inventor F.J. Cartazzi, formerly of the Great Northern Railway. It should not be confused with a

pony truck A Bissell or Bissel truck (also Bissel bogie or pony truck) is a single-axle bogie which pivots towards the centre of a steam locomotive to enable it to negotiate curves more easily. Invented in 1857 by and usually then known as a ''pony truck'' ...

as it does not pivot at all. The axle does, however, have sideways play built in to accommodate tight curves. Cartazzi's design causes the weight of the locomotive to exert a self-centring action on the trailing wheels. The Cartazzi design was also sometimes applied to

driving wheel On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons (or turbine, in the case of a steam turbine locomotive). On a conventional, non-articulated locomotive, the driving wheels are all coupled t ...

axles on longer wheelbase locomotives.

Modelling

On small scale models the trailing wheels of Cartazzi-axled locomotives are often flangeless to allow negotiation of tighter, non-prototypical curves, or the Cartazzi axle has been replaced with a

for the same reason.

References

External links

Cartazzi, Francis James
at Steamindex Steam locomotive technologies Bogie {{steam-loco-stub