Good evening all.   Does anyone have (or can point me in the direction of a good source) a simple dimensioned drawing or diagram of the typical self-contained buffers used on GWR wagons?     I believe that there were some variations in the size of the buffer head over the years (11", 12", & 13" (or 1'3"?)) so I wouldn't be too surprised if there various answers to the question.   Unfortunately I'm not in a position at the moment to go and measure one so I'll have to hope someone out