Les,
My 1/76 Vernon diorama includes scale 600' of FBE (with 2 centre bays being replaced due to sheel fire) and Bailery Pontoon being built (same span but under construction).
AB make cast white metal Bailey bridges; they have currently supplied me with 500x Bailey panels, 300x Rakers, 200x Transoms 60x Pontoons etc......
There website is well worth a look:
http://www.abfigures.co.uk/british_b..._equipment.htm
FBE MkIII is resin casting from Trux (no longer in business).
(Very) slowly taking shape!
David