If you want a single throttle postwar transformer, the LW is the best IMHO. Great look with the green light, separate whistle and reverse buttons (no bell button). Also the highest power output of an PW single throttle transformer.
I have a modern Lionel BW transformer from a 2002 set I'd be willing to sell. It has a single throttle that's separate from the power source (brick). Great for a single loop with chopped sine wave if that's important.
Here's what I'd really recommend. Pick up an entire Williams set that comes with a Williams 80W transformer. Here's a link to a NYC set that I own. Great O27/traditional engine and tender, 3 pieces of rolling, some fairly useless Industrial Rail track unless you want an isolated loop, and the transformer for under $200. https://www.trainz.com/collect...am-freight-train-set. To me, this set is the best O27 bargain on the market. It's a great little steam engine worth the value of the entire set, so you get rolling stock and a transformer essentially for free.
For a bit more money, you can get a small Williams diesel in a set with passenger cars at Marios complete with a transformer. These transformers have separate whistle and bell buttons that postwar transformers lack. https://www.mariostrains.com/i...id=17&Itemid=529. This solves your desire for a small Williams diesel WITHOUT DUMMY while also getting you a transformer. Think of it this way. $100 for the engine, $100 for the transformer, and $100 for 3 passenger cars in this set.
Williams offered this same set in the Pennsylvania road as well as shown in their 2011 catalog, but I haven't seen one on the market in a while. http://www.williamstrains.com/2011/2011_williams.pdf