I think we have to be a bit careful here about slating who every welded the beam when the owner of the bus has stated in the gallery thread that he hit a raised manhole cover with the beam end plate but hasn't mentioned it in this thread.
Hitting the beam end plate on anything hard is likely to cause damage, admittedly more than I would have thought but the beam didn't just 'snap' as this thread suggests.
This is already being talked about on Facebook as a misleading thread with a link to this site which isn't good for the forum overall.