John Palmer
Active Member
Looking at the Siphon J pictured at Stranraer, I was struck by the distance between the wheelsets in each bogie. The Diagram O31 Siphons J were produced with seven foot wheelbase bogies, and it seemed to me that the one pictured was carried on bogies of greater length. A bit more research required...
I don't have either Jack Slinn's original work on the Siphon family or John Lewis' more recent treatise on the subject. The information available to me does, however, indicate that a further ten Siphons J were built to a different diagram, O40, and completed in 1934. There appears to have been a six inch difference between the two diagrams' wheelbases, which suggests to me that the O40s were fitted with a different design of bogie, presumably one of the nine foot wheelbase types – which is what I think I can see beneath the one at Stranraer. This also appears to be confirmed by the data in Longworth, in which the O40 design is illustrated with a 9' 0" wheelbase plate bogie.
Incidentally, I was wrong about the number of O31s built: one lot of 8 and one lot of 27, making 35 in total not 32.
No doubt someone having more than my rudimentary knowledge of GW Brown vehicles will correct me if I've got this wrong.
I don't have either Jack Slinn's original work on the Siphon family or John Lewis' more recent treatise on the subject. The information available to me does, however, indicate that a further ten Siphons J were built to a different diagram, O40, and completed in 1934. There appears to have been a six inch difference between the two diagrams' wheelbases, which suggests to me that the O40s were fitted with a different design of bogie, presumably one of the nine foot wheelbase types – which is what I think I can see beneath the one at Stranraer. This also appears to be confirmed by the data in Longworth, in which the O40 design is illustrated with a 9' 0" wheelbase plate bogie.
Incidentally, I was wrong about the number of O31s built: one lot of 8 and one lot of 27, making 35 in total not 32.
No doubt someone having more than my rudimentary knowledge of GW Brown vehicles will correct me if I've got this wrong.