The Lionel LW Trainmaster is a 125 watt transformer that Lionel produced from 1955 to 1966. They are reasonably durable and Lionel made them for a long time. That means you can find them easily on the secondary market. They can be expensive if they have their original box and paperwork. But if you just want to run a train and don’t care about the paper, you can get a serviced LW for $50-$60, and an as-is one for under $40. At 125 watts, it’s the most powerful single-handle transformer of the postwar era.
The LW is a quirky transformer so there are some things about if you need to be aware of if you have other Lionel transformers, but as long as you keep those in mind, it’s a fine transformer that will serve you well. The quirks have nothing at all to do with reliability. Lionel just designed its layout a bit differently than many of their other models. In some ways it’s the ideal accessory transformer. We’ll cover that later.
One thing to keep in mind: Unplug the LW when you’re not using it. It doesn’t have its own power switch. I plug my transformers into a power strip and turn all of them on and off with the strip’s on/off switch.