This is taking shape nicely Barry.....There's just one thing bugging me and I realise we all have our own interpretations when constructing dios., particularly the effects of explosions, but the rails don't look quite right to me.
I would suggest that to destroy and bend the rails as you have them would taken a colossal explosion, leaving nothing left of the bridge, scattering the structure far and wide, leaving only small shards of timber and rubble. Destroyed wooden rail bridges usually have at least the rails intact hanging in mid air, sometimes with some sleepers still attached....Just my own thoughts.
I daresay eyebrows will be raised by my suggestion, but that is all it is, and I agree with Jim that you are open minded to receive, as I see it, my well meant observation.
The initial wrecking of the bridge is first class. It does take a bit of steeling yourself to deliberately destroy work that has been stuck together, but it's the only way to achieve any sort of realism.
Excellent work thus far......
Ron