Good modern locomotives for pulling Postwar operating cars with sliding shoes are not limited to those with speed control like Proto 2 and 3 and Lionel LC+, Legacy, etc.
There are K Line and Williams engines without speed control that are also slow smooth runners, especially pulling a heavy load. I had my K Line GP38 Chessie System diesel pulling 11 Postwar coal dump cars and caboose this morning at a snail's pace without risk of snagging any sliding shoes. Will post a video showing this later. Arnold