Richard,
I would say that they were an early version of a Buckeye 70-Ton truck. I used to see an updated version of this type of truck beneath Bessemer & Lake Erie triple hoppers when I worked as a PRR operator at Stadium Tower in Greenwich Yard in South Philadelphia in 1967-1968. Greenwich was a destination for coal trains of export coal at the time and a good third of the loaded hoppers were B&LE triples with the later version of the Buckeye truck. Indeed, the horns were the support for the brake beams and outside clasp brakes.
Best regards,
Tom Olsen
7 Boundary Road, West Branch
Newark, Delaware, 19711-7479
(302) 738-4292
tmolsen@...