All the bridges, everywhere, so in Ukraine, Russia or Hungary too, are over-engineered with safety margins at least 1,5-2x as necesarry. So, if some bridge is limited for say 40 t, that means that it will not collapse without 60-70 t at least. I once crossed over a 5 t-limit bridge with a 15 t bus- and? Nothing happened.
Dont forget the 60 tons tweight is only for tank, the traile+ truck additional 42-43 tons.
Means an abrams on transport 110 tons with the truck+trailer.
So, at the bridge they unload the tank, its pass on its own, overloading only by 50% the bridge, and on the other side goes back : D
Lot of way to pay, but the main problem is the tank itself has an only 5 meters long contact area.
Means on many places the trailer train will be less stress tothe bridge with its 110 tons than the single tank with its 60 tons.
Quite complicated, in practice every bridge needs individual assesment , the typical weight loads for long trucks , not for small but extremly heavy tanks.
And these are only for slowly, nicely transport the tank on the bridge.
If there is a need for higher speed, with applying the breaks or turning the train then the bridge can jump off from the dilatation supports.
