The Saddle Tank has long been a favourite for Mamod buyers and this year marks the dawn of the latest incarnation of this popular model.

Despite being unnamed as of yet, there is already excitement and anticipation of this new Saddle Tank to come off the Mamod production line. The company waved goodbye to a stalwart of the Smethwick factory when the final Diamond Jubilee Saddle Tank engine was sold in the build-up to Christmas. Mamod now has high hopes that the new model will strike the same chord with enthusiasts.

So why has the Saddle Tank become such a popular model? Well, Mamod engineers believe the limited edition engine for the Queen's Diamond Jubilee has driven this popularity. This has since been complemented with the launch of the Brunel which was one of the very few steam models to have a vertical boiler as opposed to a horizontal one. This has proved to be a unique selling point for Mamod customers.

However, despite the recent success the Saddle Tank has been an institute of Mamod since the 1980s. The original Saddle Tanks were first launched in 1980 – the RS1 and the RS2. Released in 0 gauge there was only a limited number of the engine due to the small range of rolling stock and track. It represented the first mass produced live steam set to be sold in the UK.

They remain the last remnants of the Malin family's ownership of the company but the success of the RS1 and RS2 inspired the development of the RS3. This model hit the shelves just a year after the original launch of the first two, this was shortly followed by the SL1 kit in 1983. These engines saw the introduction of a pair of double acting oscillating cylinders connected to a rotary reversing valve.

What's the difference?

When it comes to the Saddle Tank there are a number of considerable differences between these engines and the other engines in Mamod's portfolio. The name itself is derived from the fact that the water tank cover saddles the boiler. It was a design that was used in real life engine around the world and was popular with smaller, industrial trains.

Both in real life and in model form, the design of the Saddle Tank was popular as it allowed for greater water capacity compared to the traditional side tank arrangement. The close proximity to the boiler meant that the liquid could be pre-warmed and smooth the transition into the engine, making it much more efficient.

Mamod made a few tweaks when it came to design a model Saddle Tank compared to the real locomotives, while they work in the same sense there are a number of differences when it comes to the design. The model versions do not have a separate water tank and the water is placed directly into the boiler.

The Saddle Tank continues to be a huge favourite in the modelling and has even tried to be replicated by another company before production was ended.