On Saturday evening two bridge decks were replaced on on overpass on the major highway which runs through Ottawa. A conventional approach would take the best part of two years, complete with the associated disruption to traffic. This new 'switch out' process was done in just 17 hours. This was made possible by using drivable hydraulic lifting machines to remove the old bridge decks and then place new decks which had been built nearby. The sketch was earlier in the day when the crews were positioning the lifting machine. I was disappointed to not be able to get close to the machine, which would have been a more interesting subject on its own.