The story of what happened to the GE19 bridge last night is starting to become clear. The bridge had been jacked up to remove its temporary support brackets and lower it onto its permanent ones. The jacks failed and the bridge dropped a few inches, causing concrete debris to fall onto the track below - either parts of the deck or of a damaged support column.
We don't know much more than that, but I can explain a bit about this bracket business. When the bridge was moved into place, it needed to slide easily, so they placed these metal runners atop the concrete columns:
These needed to be replaced with something that held the bridge more securely, and here's the same column today:
The bridge is secured directly to the column with a couple of metal plates.
What we've still to find out is what they were doing at the time the jack collapsed, and which corner of the bridge the accident occurred at.
In any case, Network Rail really aren't happy about this "fiasco":
Because of concerns over TfL's handling and management of both the project and its contractors, Network Rail has banned work on the bridge, effective immediately. This will remain in place until TfL has completed an investigation and reported back on the causes of the incident and what measures it will be putting in place to prevent a repetition.What is it with Network Rail banning TfL from their new bridges?