A Rivarossi 1539 HO gauge 4-6-6-4 Challenger steam locomotive and tender number 3978 in Union Pacific "Greyhound" grey livery with Union Pacific printed in silver coloured lettering on a darker grey stripe on the tender sides. This version of the model also features smoke deflectors.

It is very well detailed and features aluminium effect smoke-box and ash-pan, cow-catcher, brass effect bell and "centipede" tender. 

The model is in excellent condition with no significant wear and no damage to the livery. It appears to be fully intact with no detailing missing and no breakages. The drive wheel frames articulate correctly. 

On the track, it runs in both directions and the valve gear motion is good but it is a noisy runner (see video) and the motor may need some attention. 

It is supplied in its original Rivarossi outer box. Original internal packing is absent but the model will be very well packaged and protected in the post.