The AB Test Rack.
1945 Westinghouse The AB Freight Brake Equipment Instructions no.5062
Instruction Pamphlet No. 32 AB Freight Brake Equipment The New York Air Brake Co
1935 Air Brakes and Train Air Signal "AB" Freight Brake Equipment Diagrams #99-A
1968 Westinghouse ABD Freight Equipment Valves Instructions no.5039-19
1962 Fascimilie Polmadie Freight Railway Engine Workings Scottish Region