A long time ago, when steam locomotives were the dominant motive power on railroads, there existed a need for a type of engine that could shuttle cars around without smoke, steam, and cinders. These little engines were used in mines, munitions factories, chemical plants, and anywhere there was a potential for an explosion or fire, or where smoke needed to be minimized.

One method was to use a fireless steam locomotive. A "boiler" was filled most (85%) of the way with hot water, and the rest with steam from a stationary boiler on site. As the little engine worked, the drop in steam pressure caused some of the hot water to flash into more steam. A well-designed fireless engine could shuttle cars around for up to 8 hours between refillings.

Another method was via a compressed-air engine. It took compressed air (upwards of 1,000 psi), and powered cylinders like a steam locomotive. These were extremely simple machines, and saw great success in mining companies, where their low profile could be fully utilized.

The last method included in this pack was via a small diesel or gasoline engine. Usually a small engine (< 20 bhp) would power the wheels via a mechanical linkage, whether it be chains or gears.

Many of these little engines were built for use on narrow gauge and temporary track. In this instance, these engines are built to about a 30" gauge in HO scale (HOn30). This means that with a real-life gauge size of 9 mm (8.8mm on the models), these little engines can be placed on N-scale track, perfect for simulating a small, industrial narrow-gauge route.

Included in this set are:

• 2 types of frames (Pistons and connecting rods, and no pistons and no connecting rods)

• 3 types of cabs (One large front window, two small front windows, and an open air cab)

• 3 types of motive power (Fireless steam "boiler", compressed air cylinders, and diesel/gasoline)

These models are static; the wheels are unable to turn. They are meant to be a prop, not an actual model locomotive.

All components are interchangeable with each other; if you want a fireless boiler with an open cab and a non-steam frame, the pieces will fit seamlessly. All pieces are designed to be built without supports, but I highly recommend building a raft with these.

The motive power and cab pieces should be arranged upright, as they would appear on the model. The frames should be flipped upside-down, as this allows the wheels to be built more easily.

I've got some matching railcars (carts?) coming along in the works. I'm thinking that you could use a staple or wire for coupling the cars and locos together.