No argument there, I was just quoting from the general appendix which uses the name "Alliance" to differentiate between the fixed and the drop...
What you say is quite correct.
Quoted from British Railways General Appendix To Working Timetable BR 29944 June 1981 "Screw couplings" 2.5 When a vehicle fitted with a BR screw...
You are confusing Buckeyes used on Pullman gangways in your photograph with "Alliance" Buckeyes that are used on class 253/254 trains. The latter...
Quoted from British Railways General Appendix To Working Timetable BR 29944 June 1981 "Coupling and uncoupling of vehicles " 3.1 "Vehicles fitted...
You cannot use a screw coupling on a vehicle fitted with Alliance couplers because they are incompatible.
أفصل بين الأسماء بفاصلة.