It is very interesting, but I am not sure I understand the reasoning. At first, I thought they were just trying to get the train over the crossing on a one-time basis. But, after watching the whole thing, it appears that they used the train as a tool to open the crossing for continued use.
For all the work that entailed (and risk of damage), it seems like it would have been easier to just use power equipment to break out the pavement. I get the impression that they may have used power equipment in conjunction with the locomotive, but that is not really shown. Maybe it was preferable to use the locomotive to cut the exact profile in the pavement to fit the train, and no more. If so, it looks like quite the speed bump for the road.