Under-frame details for North British D71 Full Brake

[Robpulham]

Good afternoon all,

A friend and I are currently building a couple of Bill Bedford NBR D71 Full Brake kits and I am struggling to find under-frame details. I have managed to get a hold a of copies of a few photos of NBR coaches which include a couple of BG's. But while they help on the exterior details they are lacking in visibility of under-frame detail.

I have also borrowed NBR Coaches A Design Review by GWM Sewell from the library. So far I haven't come across any details of what's underneath.

Bill did kindly correct my initial placement of the battery boxes and queen posts but what I am struggling with now is:

1.Placement of and number of Vacuum Cylinders - was there just one or did two operate from the same V hangers similarly to some of the NER coaches? - There is only one set of V hangers etched into the floor pan that fold down.

2.Did they have vacuum tanks - the basic Sewell drawings seem to suggest they might but they could in fact be the battery boxes. It's hard to tell as the drawings are not detailed.
3.
Which end did the Dynamo fit?

Thanks in advance to anyone who can assist or point me at any further reference material.

[Bill Bedford]

Complicated, mainly because there were three batches with different underframes. I have the original GA for these underframes, the later descriptions are taken from photos.

The first three, built 1906, had three battery boxes, as on the kit, and Westinghouse brakes. The brake cylinder was mounted centrally but offset towards the side opposite to the split battery box. The dynamo was between the split battery box and the bogie on the same side.

Some time after 1912 they were fitted with vacuum brakes. The box on the same side, but at the other end as the split box was removed and a brake cylinder put in its place. A second brake cylinder would have been fitted diagonally opposite, i.e. at the same end, but on the opposite side to the split battery box. The brake cylinders were towards the bogie and the cross shaft about 18" from the queen posts.

The 1912 batch were built as dual braked with the vacuum cylinders as above and the westinghouse cylinder placed centrally, but on the opposite side to the original batch. There were two battery boxes, one placed centrally on the opposite side to the westinghouse cylinder and the other outside the queen posts on the same side. This batch seems to have had LNER type queen posts. The photo I have of one of the first batch also has this type of queen post, but since it is taken late in the coach's life I don't know it it is original or a replacement.

All the vehicle would have lost their westinghouse brakes after the grouping. I can't see any evidence of vacuum tanks.

[Robpulham]

Thanks Bill,

That's much appreciated.