Those are Verona trucks, and not T-section. They've been discussed before on this list. Search the photos section for "Verona".
The truck under NYC 915419 has the typical spring group for conventional 70-ton trucks when the car was built (circa 1924?). That was 5 springs per side frame in a 2-1-2 pattern, and that middle spring can be seen in the photo. By comparison, 40-50 ton trucks had only four springs, grouped close together.
Tahoe Model Works
Carson City, NV