If you’ve ventured inside a hobby shop in search of a power pack for your model railway having discovered that the power pack the train set came with is wholly inadequate you’re not alone. Many have walked through those doors before you. When you make that trip, however, realize that there are several considerations you need to ponder before choosing the power pack that’s right for you and your layout.
Some of the things to ask yourself include what size will my layout eventually be and what requirements might that size make on the power pack? What scale am I working in? How many different engines and accessories will be run off this power pack? All these things and more need to be answered before you can make an intelligent purchase. Doing it ahead of time as much as possible makes the shopping easier and can stave off problems.

Since the current needed to power a model railroad is not large, transformers and power packs do the job of converting normal 110-volt AC house current into the low doses (0-20 volts) needed for model trains. Most power packs have a built-in transformer, and do the job nicely.
Some large scale trains are run on AC current, and it’s gonna be up to you to know which current your trains run on. The type of current needed can be found on the product specifications. Most Ho or N scale trains run on DC power, and virtually any power pack will work. (Except for trains from Marklin, which only run on AC supplied by a Marklin power pack.) Z scale also runs off DC , while O scale takes AC. To be safe, always look to the product specs before committing to a power pack.
Each power pack is rated by the load it must carry, so it’s important to know this information going in. The number of trains and accessories is the factor to be considered, not necessarily the amount of track you have laid. Each transformer has a limit to what it can supply, so careful planning is worthwhile. Some modelers have several power packs to furnish their needs to several different areas of their layouts. This can solve the problem of having a power drain when more than one electrical load is called upon.
As you can see, the planning and utilization of the proper power pack for your system is one to take some time with. Give it some thought!
