A Cartazzi axle is a design of leading or

trailing wheel On a steam locomotive, a trailing wheel or trailing axle is generally an unpowered wheel or axle ( wheelset) located behind the driving wheels. The axle of the trailing wheels is usually located in a trailing truck. On some large locomotives, ...

support used worldwide. The design was used extensively on the former

LNER LNER may refer to: * London and North Eastern Railway, a railway company in the United Kingdom from 1923 until 1947 * London North Eastern Railway, a train operating company in the United Kingdom since 2018 * Liquid neutral earthing resistor, a typ ...

'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 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