Been admiring the March cover of MR, nice pair of AB FT units in the pre McGuinis maroon and gold paint. I just noticed the large roof vent/fan/what-is-it gizmo's on both units. Any one know what they really are? They are prototypical, I see them in a number of Arthur Mitchell photos of B&M FT units. The unit on the MR cover photo is numbered
4201, which is probably real, I have photos of 4204 and 4210 so a 4201 is perfectly plausible.David J. Starr