Standard Gauge Passenger Steam Engine Os24

A big steam engine designed to high traction yet be able to run on weak track.

The rather uncommon axle arrangement gave the engine some unique characteristics – aesthetic and functional. Notably, the designation lead to it being nicknamed “Osa” – the Polish word for wasp.


The picture at the right shows a model of the Os24 at the Warsaw Train Museum. You can get a collector’s mug with an image of the Os24 on it. Information about that can be found by clicking here. Railroad Mugs

Also get a quick overview at the SpecialGiftsStore

O – Passenge Locomotive
s – axle Arrangement – 2-4-0
24 – Initial year of production.

The railroads in the Southern part of Poland were characterised by weak track. So engines had to have a low axle load.

The 2-4-0 axle arrangement offered a low axle load with high traction capability.

The wheel arrangement required that the boiler be mounted high so the firebox had sufficient clearance. This gave the engine a unique and attractive appearance.

Speeds were limited due to instability at around 80 km per hour.

There is one surviving specimen that you can see at the Warsaw Train Museum.

And you can read a lot more about the history of the Os24 at



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