We seem to have gone a bit off topic with this, but it isn't unknown for the BSA/Triumph triples to throw the odd conrod!
The main (but by no means only) reason for this is low oil pressure, and can be the result of wear in the two centre main bearings, the alloy rods can also suffer breakage through fatigue due to the fairly revvy nature of these engines now 30+ years old, many owners upgrade to either Carrillo or Arrow steel conrods.
The triple conrod bolts are I think no weaker than any similar type, but of course they should ALWAYS be replaced with new ones (and nuts) on every stripdown, many people preferring to set the bolt torque by the measuring the amount of bolt stretch.
A LARGE amount of triple info can be found on the excellent Triples on line website forum (searchable) here:
http://www.triplesonline.com/