Hello Jeff C
Well, some advice, unfortunately; The CTA Chicago (MTH CTA 30-2477) Cars are much shorter very vaguely similar cars to the longer and wider Broad St Subway B-4 Subway Cars.
The prototype Chicago EL Cars -(per MTH set 30-2477)- bodies are just inside 9 feet wide x 48 feet long ---
The prototype Broad Street Subway B-4 car bodies are 10 feet wide x 67 feet long
See Images below attached comparing both body types; Your cursor placed over the photo shows the caption;
You could get a few 2 car ADD ON sets and cut up the body panels to create the proper window (W) and door (Door) spacing arrangement for the Broad 4 cars as follows: W - Door - W-W-W - Door - W-W - Door - W-W
Compare that with the CTA Car image above !
However, the BOTTOMS of the door windows on the B4 Car are also located quite higher up than those on the CTA Car Model doors !
By the way - the 2nd photo above shows the HO Scale MODEL of the Broad St Subway B4 Car created by Island Model Works -- This could be done in O-Scale if enough valid support comes thru !
BELOW is a rare and unusual image of CTA EL Car 2211 of the CTA 2200 Series, shown in PTC-SEPTA Fern Rock Yards of the Broad St. Subway among the Broad Street Line's original standard stock -- this view from August 24, 1969 (47 years ago !) . LONG BEFORE some second hand CTA EL cars were brought to Philly to run on the standard gauge track (as Broad St Subway track is) of the Red Arrow Lines Norristown Hi-Speed Line !
Regards - Joe F