I didn't mean to suggest that a weld can handle all jobs, but nor should it be ruled out completely. You assume one kind of break, and thus one kind of explanation--whether that fits this case or not is impossible to say, and it in no negates my suggestion, as it is based on personal experience, and, well, it worked. Extreme downward force, such as incurred when riding an MTB down a steep and rocky slope, butt high in the air, and then smacked down on the seat, could easily supply enough force, irrespective of "leather tension"--so, if the break is along one of these rails, and as long as it isn't in an intrusive area, then possibly it I can be fixed by welding, BUT as noted above, if not, I do have a few extras (for the last 15-20 years or so, I have only used Brooks saddles on both my MTBs and Roadies, so I know them pretty well--and now must have close to 10 in the bike shed--at least 2 of which aren't on bikes, and thus available as necessary.)When rails snap on a Brooks it tends to be due to insufficient tension on the leather, which causes the rails to be stressed right at the edge of the clamps grabbing them from above and below to attach them to the seat post. Any welding to repair the crack must not obstruct these clamps. I don't see how that could easily be achieved by adding a steel plate above or below, especially as there's a bolt that pulls those two clamps together.