Leading wheel

Leading wheels are used to help the locomotive negotiate curves and to support the front portion of the boiler.

Many leading bogies do not have simple rotational motion about a vertical pivot.

Bogies with a sliding motion controlled by springs was patented by William Adams in 1865.

Locomotives without leading trucks are generally regarded as unsuitable for high speed use.

[2] Other designers, however, persisted with the practice and the famous 0-4-2 Gladstone class passenger expresses of the London, Brighton and South Coast Railway remained in trouble-free service until 1933.